Midterm Review Flashcards by Yahnsen Wagner

At the end of an experiment, what might you do after data has been analyzed?

A. create a bar graph
B. examine a picture
C. draw a conclusion
D. produce a hypothesis

C. draw a conclusion

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Which of the following best describes matter?

A. the “stuff” that everything is made of
B. the “stuff” that makes up the atmosphere
C. the “stuff” that is large enough to see
D. the “stuff” from outer space

A. the “stuff” that everything is made of

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In an experiment to determine if the popping of popcorn is affected by the temperature at which it is stored, counting the popped kernels is an example of a(n)…

A. conclusion
B. independent variable
C. control
D. dependent variable

D. dependent variable

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A factor that does not change in an experiment is also known as what?

a constant

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What step of the scientific method could lead to the process starting over again?

A. conduct an experiment
B. make observations
C. draw conclusions
D. form a hypothesis

C. draw conclusions

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A standard for comparison that helps to ensure that the experimental result is caused by the independent variable is a…

A. dependent variable
B. independent variable
C. constant
D. control

D. control

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What is a statement about what happens in nature and that seems true all the time?

A. a hypothesis
B. a scientific law
C. a theory
D. a conclusion

B. a scientific law

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A good model makes _______ ideas ______.

A. scientific, unscientific
B. imaginary, real
C. simple, complex
D. complex, simple

D. complex, simple

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What type of model uses data to explain a concept?

mathematical

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The scientific process begins with asking questions and…

A. making observations.
B. answering them.
C. reading background.
D. planning experiment.

A. making observations.

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Once you’ve asked questions and made observations, you are ready to…

A. formulate a scientific theory.
B. conduct experiments.
C. form a hypothesis and test it.
D. draw conclusions.

C. form a hypothesis and test it.

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What model exactly resembles the concept it represents?

physical

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A weather map of the Greater Rochester Area is an example of a…

A. physical model
B. all of the above
C. mathematical model
D. conceptual model

C. mathematical model

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Which of the following best fits the definition for the dependent variable in an experiment?

A. the conclusions drawn at the end of the experiment
B. what must stay the same throughout the experiment
C. the aspect of the experiment that is altered or changed
D. the part of the experiment that the experimenter measures or pays attention to

D. the part of the experiment that the experimenter measures or pays attention to

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A testable explanation based upon observations is a(n)…

A. variable
B. exercise
C. hypothesis
D. experiment

C. hypothesis

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What do scientists use to represent a system or an object?

a model

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Early scientists thought the shapes of birds’ wings helped birds fly. In their first experiments, they made wings the same thickness and shape from front to back. This didn’t work. What might these scientists have done after they analyzed their results?

A. taken a vacation
B. designed new wing shapes
C. stopped conducting tests
D. given up on the hypothesis

B. designed new wing shapes

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True or false: Scientific theories can change over time as more data is gathered.

True

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A(n) … occurs when what the scientist expects changes how the results are viewed.

A. Bias
B. Control
C. Hypothesis
D. Theory

A. Bias

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What are the steps that scientists use to answer questions and solve problems?

scientific method

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Which of the following is NOT an example of a physical model?

A. a globe
B. a map
C. a pie chart
D. a skeleton

C. a pie chart

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A study on the effects of nuclear waste should not be conducted by scientists at a nuclear power plant because of the … the plant employees may have.

A. Bias
B. Dependent variables
C. Independent variables
D. Controls

A. Bias

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An organized process used to gather data and test a hypothesis is a(n)…

A. theory.
B. hypothesis.
C. experiment.
D. conclusion.

C. experiment

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Why do scientists use models?

A. It is an easy system and the least reliable.
B. It helps them explain a complex idea or theory.
C. It allows them to create a more complex picture of a concept.
D. It is required from the scientific method.

B. It helps them explain a complex idea or theory.

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Measuring something is one way of... **A.** conducting experiments safely. **B.** making models. **C.** analyzing results. **D.** collecting data.

D. collecting data.

A topographical map of the State of New York is an example of a... **A.** mathematical model **B.** conceptual model **C.** physical model **D.** all of the above

D. all of the above ## Footnote A topographical map uses numerical data, helps people visualize and understand slopes and elevation, and is a physical representation of geographical features.

# Fill in the chart pertaining to the scientific method:

In this experiment, what is the dependent variable?

the amount of growth / height after two weeks

# What is the independent variable in the experiment below: A scientist is creating an experiment to see the affect red light has on plant growth.

The color of light (red in this case)

# What are some possible constants in the experiment below: A scientist is creating an experiment to see the effect watering plants has on their growth.

* Type of plant * Amount of water being given * Soil type * Size of the pots * Temperature * Sunlight exposure * Humidity levels

# Using the word bank, categorize the following: ## Footnote Word bank: Physical Model Mathematical Model Conceptual Model

physical model

# Using the word bank, categorize the following: ## Footnote Word bank: Physical Model Mathematical Model Conceptual Model

conceptual model

# Using the word bank, categorize the following: ## Footnote Word bank: Physical Model Mathematical Model Conceptual Model

mathematical model

What two MAIN branches of science make up physical science?

1. Chemistry 2. Physics

What is the dependent variable in the graph?

Number of Pushups

Which would be a proper title for the graph? **A.** mobile phones in 2010 **B.** Year vs. mobile phone sales **C.** years of mobile phones sold in 1 year **D.** mobile phone sales vs. year

D. mobile phone sales vs. year

Which of the following is a complex unit derived from SI base units? **A.** kilogram **B.** meter **C.** Kelvin **D.** g/mL

D. g/mL

If a substance has a mass of 3.5 g and a volume of 1.25 mL what is the density of the substance? **A.** 3.51 g/mL **B.** 2.8 g/mL **C.** 1.00 g/mL **D.** 0.693 g/mL

B. 2.8 g/mL

Which of these best defines volume? **A.** the interval between two events. **B.** the distance between two points. **C.** the quantity of matter in an object. **D.** the amount of space an object occupies.

D. the amount of space an object occupies.

Provide the term using its definition. 1. how hot or cool something is, usually measured in degrees Celcius or Kelvin. 2. mass per unit of volume. 3. the amount of matter in an object. 4. measured in milliliters. 5. an exact quantity that people use to compare measurements. 6. the variable that is assigned to the y-axis on a graph. 7. as the independent variable increases, the dependent variable decreases. 8. the variable that is assigned to the x-axis on a graph. 9. is a visual representative of data. 10. SI scale of temperature. ## Footnote Word Bank: standard, Kelvin, graph, independent variable, inversely proportional, dependent variable, density, temperature, mass, volume

1. temperature 2. density 3. mass 4. volume 5. standard 6. dependent variable 7. inversely proportional 8. independent variable 9. graph 10. Kelvin

In a graph showing how the temperature of a material changes over time, temperature change is the... **A.** variable with the smallest range **B.** variable with the largest range **C.** dependent variable **D.** independent variable

C. dependent variable

Of the following, the most correct way to express density is... **A.** g **B.** mL/g **C.** g/cm **D.** g/cm³

D. g/cm³

A beaker contains 0.32 L of water. The beaker's volume is ... milliliters. **A.** 3.2 **B.** 0.032 **C.** 32 **D.** 320

D. 320

A measurement standard is defined as... **A.** a system of prefixes **B.** the distance between two points **C.** an exact quantity people agree to use for comparison **D.** the interval between two events

C. an exact quantity people agree to use for comparison

Of the following, the only unit that cannot be used to express volume is ... **A.** kg **B.** L **C.** cm³ **D.** mL

A. kg

# The following units are examples of what? * **Density**: g/cm³ * **Velocity**: m/s * **Acceleration**: m/s^{2
* **Momentum**: kg*m/s
* **Weight**: kg*m/s² (also known as the Newton or N)
* **Energy**: N*m (also known as the Joule or J)
* **Power**: J/s or N*m/s (also known as the Watt or W)}

Derived units ## Footnote Most derived units look different from regular SI units, so you should be able to tell them apart

# Complete the statement with the best available option: For most scientific work, temperature is measured on the... scale. **A.** Kelvin **B.** Farenheight **C.** Celsius **D.** Ketanji Brown Jackson

C. Celsius

What is the SI unit of temperature?

Kelvin (K)

# Complete the statement with the best available option: Time is usually the ... variable **A.** dependent (Y-axis) **B.** independent (X-axis) **C.** constant **D.** None of the above

B. independent (X-axis)

The X-axis information should be on which side of the data table?

Left

Is the graph below directly proportional or inversely proportional?

Inversely Proportional ## Footnote **Inversely Proportional** - As the independent variable increases, the dependent variable decreases

Is the graph below directly proportional or inversely proportional?

Directly Proportional ## Footnote **Directly Proportional** - As the independent variable increases, the dependent variable increases as well

# Answer the question with the best available option: What tool might somebody use to measure precise amounts of liquid volume? **A.** ruler **B.** scale **C.** gradulated cylinder **D.** beaker

C. graduated cylinder

``` A metal box has a mass of 500 grams. The box has the following dimensions: a length of 10 cm, a width of 5 cm, and a height of 4 cm. ``` **Determine the density of the metal.**

2.5 g/cm³

``` A rectangular box has a length of 5 meters, a width of 3 meters, and a height of 2 meters. ``` **What is the volume of the box?**

30 m³

Create a scale for the x-axis and the y-axis.

* **x-axis** - 1 * **y-axis** - 1 ## Footnote Reminder: To create a scale for a graph, you have to calculate the range of the given data, then divide it by the number of squares (spaces) available.

Create a scale for the x-axis and the y-axis.

* **x-axis** - 0.5 * **y-axis** - 3

# {screenshot then import to Notability, check graph with answer key}

#Fill in the chart:

# Provide the metric units for: * length * mass * volume * temperature * density

* meter (m) * kilogram (kg) / gram (g) * cubic meter (m³) / Liter * Kelvin (K) / Celsius (˚C) * Kilograms per cubic meter (kg/m³) ## Footnote The unit for density is simply mass / volume.

``` A block of metal has a mass of 240 grams and occupies a volume of 30 cubic centimeters. ``` **What is the density of the metal?**

8 g/cm³

What tool would you use to find a liquid's volume?

a graduated cylinder or beaker

The International System of Units (SI) is based on the ______ system.

metric

# Use Pickett Fence Convert 42.5 dozen to gross. ## Footnote 1 gross = 12 dozen | 1.2 dozen = 1.108 baker dozen | 1 baker dozen = 6.5 pairs | 0.25 pairs = 0.125 particles | 6.02 x 10²³ particles = 1 mol

3.54 gross

# Use Pickett Fence Convert 12.54 gross to particles. ## Footnote 1 gross = 12 dozen | 1.2 dozen = 1.108 baker dozen | 1 baker dozen = 6.5 pairs | 0.25 pairs = 0.125 particles | 6.02 x 10²³ particles = 1 mol

451.57 particles

True or false: Acceleration is the rate of change of velocity.

True

True or false: A reference point is needed to determine the position of an object.

True

... is how far an object has moved in total. **A.** displacement **B.** velocity **C.** distance **D.** rate

C. distance

... is the distance and direction of an object's change in position from the starting point. **A.** velocity **B.** speed **C.** displacement **D.** rate

C. displacement

... is the distance an object travels per unit of time. **A.** velocity **B.** speed **C.** rate **D.** displacement

B. speed

... is the total distance traveled divided by the total time of travel. **A.** total speed **B.** displacement **C.** average speed **D.** distance

C. average speed

... is the speed at a given point in time. **A.** average speed **B.** total displacement **C.** instantaneous speed **D.** velocity

C. instantaneous speed

... includes the speed of the object and the direction of its motion. **A.** velocity **B.** speed **C.** instantaneous speed **D.** rate

A. velocity

What do you NOT need to calculate acceleration? **A.** initial velocity **B.** time **C.** final velocity **D.** distance

D. distance

Momentum, velocity, and acceleration are... **A.** vector quantities **B.** found on car dashboards **C.** scalar quantities **D.** measured in the unit m/s

A. vector quantities

Motion is defined as... **A.** an object's change in position relative to a reference point **B.** an object's change in position relative to time **C.** an object's change in speed relative to a reference point **D.** an object's change in position relative to mass

A. an object's change in position relative to a reference point

If a soccer ball has a mass of 0.4 kg and a velocity of 20 m/s east, what is its momentum? **A.** 50 kg * m/s west **B.** 8 kg * m/s east **C.** 8 kg * m/s west **D.** 50 kg * m/s east

B. 8 kg * m/s east

If you travel 1.7 km north from your house at noon, and at 6:00 PM you travel 5.4 km south, what is your displacement? **A.** 3.7 north **B.** 7.1 north **C.** 3.7 south **D.** 7.1 south

C. 3.7 south

At 8:00 AM you leave home and walk 0.5 km to a friend's house. At 11:30 AM you return home, then travel by car to the mall, which is 10 km away, and arrive at 11:45 AM. What is the total distance traveled? **A.** 10.5 km **B.** 2.8 km/h **C.** 10 km **D.** 11 km

D. 11 km

The direction and speed of an object is described by its ... **A.** average speed **B.** velocity **C.** average displacement **D.** displacement

B. velocity

What is the acceleration of the object between 6 s and 10 s? **A.** 2 m/s² **B.** 3 m/s² **C.** -1 m/s² **D.** -6 m/s ²

C. -1 m/s²

An object traveling in a circular path is accelerating because its... **A.** mass changes **B.** direction changes **C.** momentum changes **D.** speed changes

B. direction changes

Which of the following statements about momentum is true? **A.** momentum is not a vector quantity **B.** momentum increases as an object's mass increases **C.** momentum is the product of mass and acceleration **D.** the unit for momentum is the g/mL

B. momentum increases as an object's mass increases

# Provide the term using its definition. 1. An object that is neither speeding up nor slowing down travels at a... 2. The rate of change in position at a given point in time 3. Rate of change of the velocity of an object 4. The total distance an object travels divided by the time of travel 5. Grows larger with greater mass 6. Something that appears to remain in place compared to something moving 7. The total change in position ## Footnote Word Bank: Reference point, acceleration, constant speed, instantaneous speed, momentum, displacement, average speed

1. constant speed 2. instantaneous speed 3. acceleration 4. average speed 5. momentum 6. reference point 7. displacement

What would be a good title for this graph? **A.** position vs. time **B.** time vs. position **C.** time vs. speed **D.** position vs. reaction

A. position vs. time

What is the acceleration of the object between 2 s and 6 s? **A.** 3 m/s² **B.** 2 m/s² **C.** 0 m/s² **D.** 1 m/s²

C. 0 m/s²

When a moving object reduces speed that is known as... **A.** forward acceleration **B.** reverse acceleration **C.** centripetal acceleration **D.** negative velocity

B. reverse acceleration

Which of the following is NOT an example of acceleration? **A.** A car slowing down. **B.** A bike speeding up. **C.** A go-kart at a constant speed. **D.** A sprinter turning east on a track.

C. A go-kart at a constant speed.

What type of acceleration is shown via the arrow (ac) in the image below if v is velocity? **A.** projectile motion **B.** forward acceleration **C.** centripetal acceleration **D.** reverse acceleration

C. centripetal acceleration

Which pair of quantities are both scalar? **A.** speed and mass **B.** speed and momentum **C.** momentum and displacement **D.** mass and displacement

A. speed and mass

Shown below is a displacement-time graph for Bob as he walks to a friend's house and returns over a day. Which of the following statements concerning this journey is correct? **A.** The total distance traveled for the journey was 5 km. **B.** The total distance traveled for the journey was 10 km. **C.** The total displacement for the journey was 5 km. **D.** A one-hour rest break was made during the journey.

B. The total distance traveled for the journey was 10 km.

Three students, Jane, Indira, and Charlotte run in a 100 m sprint on a school sports day. The displacement-time graph of their motion is shown below. Select the alternative below that correctly orders their finish places in the race. **A.** Jane wins, Indira is second, and Charlotte is third. **B.** Indira wins, Jane is second, and Charlotte is third. **C.** Charlotte wins, Indira is second, and Jane is third. **D.** Charlotte wins, Jane is second, and Indira is third.

A. Jane wins, Indira is second, and Charlotte is third.

What distance would a cockroach, crawling at a speed of 1.5 centimeters per second, cover in an hour? **A.** 5400m **B.** 5.4m **C.** 54m **D.** 0.54m

C. 54m

True or false: Speed can be expressed negatively.

False

Distance, displacement, speed, velocity, and acceleration are all measuring what?

motion

``` A car increases its speed from 10 m/s to 30 m/s in 5 seconds. ``` What is the car's acceleration?

4 m/s² ## Footnote a = V_f - V_i / t

Graph 1 is a graph of a biker riding to a store. Describe the motion of the bike rider in this figure.

The biker first starts speeding up as he moves away from the starting point, or his home (in what appears to be constant speed). Next, the biker is at rest (or at the store), as the distance from the starting point stays the same. Lastly, the biker starts to pick up speed, but this time since the distance from home goes down, he is heading the opposite direction.

Describe the motion of the object in graph 2.

In graph 2, the object's speed is constant for a decent amount of time, meaning that it has no acceleration. More than halfway through the graph, the object starts reverse accelerating as the speed slows down.

What do the slopes of each graph represent?

In graph 1, the slope represents speed, while in graph 2, the slope represents acceleration.

Do graphs 1 and 2 represent the same object in motion? Why or why not?

No. In graph 1, the line shows the biker traveling at a constant pace in the beginning. However, there is a spot where the biker is at rest. In graph 2, there is no place where the object is at rest, because then the speed would be at zero.

``` A car is moving at speed of 35.8 m/s. ``` What acceleration would it have if it took 5.0 s to come to a complete stop?

-7.16 m/s²

``` A car has a mass of 1,000 kilograms and is traveling with a velocity of 35 m/s. ``` What is its momentum?

35000 kg*m/s

Label the image with the two types of acceleration that happen independently of one another.

What type of motion is this an example of?

projectile motion

What are the three ways an object could accelerate?

1. speeding up 2. slowing down 3. changing direction

Super woman took off at speeds faster than light to travel to Pluto. The graph represents the distance vs. time of her trip. * Along her way to Pluto, between which points is she moving the fastest? * Between what points represent her arrival? * Between what points is she slowing down accelerating? * Between what points is she heading back to Earth? * When she completed the trip, how far was she from Earth?

* B-C * D-E * C-D * E-F * 4 megameters

In a distance-time graph, what does a horizontal (----) line mean?

the object is not moving, it is at rest

Which one of the graphs shows that one of the runners started 10 yards further ahead of the other?

Graph A

True or false: In a speed-time graph, a straight line means that the object is not moving.

False. ## Footnote A straight horizontal line on a speed-time graph means that speed is constant. It is not changing over time.

``` A satellite is traveling at a rate of 120 m/s. ``` How many seconds will it take for that satellite to travel 450 km? ## Footnote reminder: make sure to convert your units

3750

Newton's first law of motion states that... **A.** when a force acts on an object, its acceleration is in the same direction as the force. **B.** when a force is applied on an object, there is an equal force applied by the object in the opposite direction. **C.** an object will remain at rest or keep moving unless a force acts on it. **D.** acceleration is calculated by dividing the force exerted on an object by the mass of the object.

C. an object will remain at rest or keep moving unless a force acts on it.

The ... is the combination of all the forces acting on an object. **A.** net force **B.** force pair **C.** momentum **D.** inertia

A. net force

What happens to the gravitational force as objects get farther apart? **A.** It increases **B.** It decreases **C.** It fluctuates **D.** It stays the same

B. It decreases

What happens to the weight of astronauts when they are in orbit? **A.** It decreases but does not become zero. **B.** It does not change. **C.** It increases. **D.** It becomes zero.

A. It decreases but does not become zero.

A car with a mass of 475 kg falls with a force of 5,000 N. Use the formula from Newton's 2nd Law to calculate the acceleration of the car as it falls. **A.** 9.8 m/s² **B.** 10.5 m/s² **C.** 2,375,000 m/s² **D.** 1.5 m/s²

B. 10.5 m/s²

According to Newton's second law, what two pieces of information do you need to calculate the acceleration of the motion of an object? **A.** mass and distance **B.** mass and velocity **C.** mass and force **D.** beans and rice

C. mass and force

An object at rest tends to... **A.** move slowly at first **B.** stay at rest **C.** wake up when their mom tells them to **D.** get in motion when acted on by a balanced force

B. stay at rest

A rocket lifting up after firing its thruster is an example of... **A.** action and reaction forces **B.** balanced forces **C.** inertia **D.** something dangerous that you should try

A. action and reaction forces

Newton's 3rd law states that forces act in... **A.** threes **B.** objects with mass **C.** pairs **D.** the same direction

C. pairs

According to Newton's 2nd law as mass increases and the force stays the same... **A.** force decreases **B.** velocity stays the same **C.** you should lose weight **D.** acceleration decreases

D. acceleration decreases

What force is necessary to move an object with a mass of 10kg at a rate of 47 m/s? **A.** 4.7 N **B.** 47 N **C.** 470 N **D.** .47 m/s

C. 470 N

A squirrel has a mass of 0.5 kg. What is its weight? **A.** 0.051 N **B.** 0.5 N **C.** 4.9 N **D.** 19.6 N

C. 4.9 N

A boy weighs 400 N. What is his mass? **A.** 400 kg **B.** 0.0245 kg **C.** 3920 kg **D.** 40.8 kg

D. 40.8 kg

An astronaut has a mass of 100 kg and has a weight of 370 N on Mars. What is the gravitational strength on Mars? **A.** 3.7 m/s² **B.** 0.27 m/s² **C.** 37000 m/s² **D.** 9.8 m/s² ## Footnote remember: formula for weight is mass times gravity

A. 3.7 m/s²

On Earth, what is the weight of a large-screen TV that has a mass of 75 kg? **A.** 0.131 N **B.** 7.65 N **C.** 735 N **D.** 75 N

C. 735 N

Two students push on a box in the same direction, and one student pushes in the opposite direction. What is the net force on the box if each student pushes with a force of 50 N? **A.** 150 N total force. **B.** 0 N as the forces cancel each other out. **C.** 50 N in the direction two students push. **D.** 50 N in the direction one student pushes.

C. 50 N in the direction two students push.

In a car crash, the unrestrained passenger will... **A.** move in the opposite direction of the car they are in. **B.** continue moving at the velocity of the car before the crash. **C.** move with reverse acceleration. **D.** feel no force due to safety restraints.

B. continue moving at the velocity of the car before the crash.

Cars are designed to crumple on impact in order to... **A.** decrease the acceleration of the car. **B.** increase the time the collision takes. **C.** increase the force the car impacts with. **D.** decrease the time the collision takes.

B. increase the time the collision takes.

What causes some objects to fall slower than others? **A.** acceleration **B.** air resistance **C.** forces **D.** gravity

B. air resistance

When a falling object reaches terminal velocity, the force of gravity ... the force of air resistance. **A.** equals **B.** is greater than **C.** is less than **D.** is unrelated to

A. equals

What is g's approximate value and name. **A.** 9.8 m/s² and acceleration of gravity **B.** 4.2 m/s² and Newtons **C.** 9.8 m/s² and air resistance **D.** 1600 m/s and centripetal force

A. 9.8 m/s² and acceleration of gravity

If the same force is applied to each of these objects which would have the LEAST acceleration? **A.** f **B.** g **C.** h **D.** j

B. g

If a helicopter's mass is 4,500 kg and the net force on it is 18,000 N upward, what is its acceleration? **A.** 9.8 m/s² upward **B.** 0.25 m/s² upward **C.** 4 m/s² upward **D.** 81,000,000 m/s² upward

C. 4 m/s² upward

What is the net force on a dragster with a mass of 900 kg if its acceleration is 32 m/s² west? **A.** 28,800 N west **B.** 28.1 N west **C.** 0.036 N west **D.** 9.8 N west

A. 28,800 N west

A car pulled by a tow-truck has an acceleration of 2 m/s² east. What is the mass of the car if the net force on the car is 3,000 N east? **A.** 1500 kg **B.** 9.8 kg **C.** 0.00067 kg **D.** 6,000 kg

A. 1500 kg

What is the net force on a sky diver falling with a constant velocity of 10 m/s downward? **A.** Newton's laws do not talk about net forces. **B.** 0 N because the acceleration is 0 at a constant velocity. **C.** 9.8 m/s² because that is acceleration due to gravity. **D.** Undefined because the mass of the sky diver cannot be determined.

B. 0 N because the acceleration is 0 at a constant velocity.

A student pushes on a 5-kg box with a force of 20 N forward. The force of sliding friction is 10 N backward. What is the acceleration of the box? **A.** 2 m/s² forward **B.** 2 m/s² backward **C.** 4 m/s² forward **D.** 4 m/s² backward

A. 2 m/s² forward

You push yourself on a skateboard with a force of 30 N east and accelerate at 0.5 m/s² east. Find the mass of the skateboard if your mass is 58 kg. **A.** 2 kg **B.** 60 kg **C.** 43 kg **D.** 15 kg

A. 2 kg

Which of these keeps the satellite moving in a circular orbit? **A.** gravity **B.** friction **C.** air resistance **D.** inertia

A. gravity

A cue ball rolls toward a billiard ball with a velocity of 1 m/s east. Both balls have identical masses. What happens to the total momentum after the two balls collide? **A.** It is greater than the original momentum of the cue ball. **B.** It is equal to the momentum before the collision. **C.** It is less than the original momentum of the cueball. **D.** It is equal to zero.

B. It is equal to the momentum before the collision.

A force is a ____ or a _____.

push, pull

``` A force is applied to the right to drag a sled across loosely packed snow with a rightward acceleration. ``` Create a free-body diagram showing the forces involved.

``` A flying squirrel is gliding (no wing flaps) from a tree to the ground at constant velocity. Consider air resistance. ``` What would a free-body diagram for this situation look like?

## Footnote Gravity pulls down on the squirrel while air resistance keeps the squirrel in the air for a while. Constant velocity does not mean the object is not moving.

What is the net force of the free-body diagram below?

400 N (north)

Provide the law of Universal Gravitation.

F = G(m₁m₂ / d²) ## Footnote * F = gravitational force between the objects (in Newtons) * G = universal gravitational constant * m₁ and m₂ = masses of the two objects (in kilograms) * d = distance between the centers of the two objects (in meters)

What are the two ways gravitational force can either increase or decrease?

* change in mass * change in distance ## Footnote more mass = more gravitational force closer distance = more gravitational force

Nathaniel's Argument: ``` No matter how far apart two objects are, the gravitational force between them never completely goes to zero. ``` Camden's Argument: ``` Wow! You are dumb as rocks. Only the objects on Earth pull eachother with gravitational force, meaning that objects far away have a gravitational attraction of zero. ``` Which student is correct?

Nathaniel ## Footnote Because the gravitational force between two objects never disappears, gravity is called a long-range force

Provide the Second Law of Motion equation.

a = F_net / m ## Footnote 1. acceleration = meters per second² 2. net force = in newtons 3. mass = in kilograms

What describes the fall of an object on which only the force of gravity is acting?

free fall

The reason why some objects fall slower than others is due to which force?

air resistance

The highest speed a falling object will reach is also known as what?

terminal velocity

True or false: If the net force on an object is zero, so is the object's acceleration.

True

The sensation when there is no support force acting on your body, making you feel as though you have no weight is also known as what?

weightlessness ## Footnote Weightlessness occurs in situations such as free falling

The momentum of an object doesn't change unless its ____, _______, or both change.

mass, velocity

What does the law of conservation of momentum state?

If a group of objects exert forces only on each other, their total momentum doesn't change

A rocket lifting up after firing its thruster is an example of...

action and reaction forces

What force is necessary to move an object with a mass of 10kg at a rate of 47 m/s²?

470 N

``` An applied force of 20N is used to accelerate an object to the right across a frictional surface. The object encounters 8N of friction. Use the diagram to determine the normal force, the net force, the coefficient of friction ("mu") between the objects and the surface, the mass, and the acceleration of the object. Neglect air resistance ``` m = ____________ a = _____________ F_net = _____________ µ = ______________ F_N = ___________

m = 31.63 kg a = 0.38 m/s² F_net = 12 N µ = 0.03 F_N = 310 N

``` A rightward force is applied to a 621-g object to move it across a rough surface at constant velocity. The coefficient of friction between the object and the surface is 0.088. Use the diagram to determine the gravitational force, normal force, applied force, frictional force, and the net force. (Neglect air resistance). ``` m = ___________ a = ___________ F_net = ___________ µ = ___________ F_g = ___________ F_N = ___________ F_app = ___________ F_friction = ___________

m = 0.621 kg a = 0 m/s² F_net = 0 N µ = 0.088 F_g = 6.09 N F_N = 6.09 N F_app = 0.54 N F_friction = 0.54 N

The force that opposes the sliding motion of two surfaces that are touching each other is called what?

Friction ## Footnote Friction comes from the Latin word *fricare* meaning "to rub"

Friction occurs because the surface of any object is _______.

rough ## Footnote Even surfaces that feel smooth are covered with microscopic hills and valleys

When two surfaces are in contact, microscopic hills and valleys of one surface stick to the tiny hills and valleys of the other surface. What is this contact known as?

microwelds ## Footnote microwelds cause friction

When a force is applied to an object but the object does not move, what is being displayed?

static friction ## Footnote The object does not move because the force of static friction balances the force applied.

If static friction is occuring, what is the net force?

zero ## Footnote The word *static* means "not moving."

What is kinetic friction?

the friction between moving surfaces

After static friction disappears when an object starts moving, what type of fricton immediately occurs after?

kinetic friction (rolling or sliding)

The amount of kinetic friction between two surfaces depends in part on how the surfaces _____.

move

What are two types of kinetic friction?

* Sliding Friction * Rolling Friction

What type of friction opposes the motion of two sliding surfaces sliding past one another?

sliding friction

Sliding friction is caused by __________ constantly breaking and forming as objects _____ past one another.

microwelds, slide

Where does rolling friction occur?

between the bottom of a wheel and the ground

True or false: Sliding friction is helpful when driving.

False ## Footnote Rolling friction is helpful when driving

What type of friction is also known as traction?

Rolling friction

A region of space that has a physical quantity (such as force) at every point is also called what?

a field ## Footnote Because objects do not have to be in contact, gravity is sometimes discussed as a field

# What law of motion is being described? The natural behavior of a body is to move in a straight line at a constant speed. This means that every object will remain at rest or in uniform motion unless acted on by an unbalanced force.

Newton's First Law of Motion

# What law of motion is being described? For every action there is an equal and opposite reaction.

Newton's third law of motion

The tendency of an object to resist any change in its motion is... **A.** acceleration **B.** velocity **C.** inertia **D.** force

C. inertia

The ______ states that if a group of objects exerts forces only on each other, their total momentum doesn't change.

law of conservation of momentum

In free fall, the only acceleration is that of ... **A.** air resistance **B.** velocity **C.** turbulence **D.** gravity

D. gravity ## Footnote Therefore, the acceleration due to gravity is 9.8 m/s²

True or false: In a car crash, any passenger not wearing a safety belt continues to move forward at the same speed the car was traveling.

True

What is the function of a seat belt during a car crash? **A.** to reduce the force exerted on the person. **B.** to prevent the person from being thrown out of the car. **C.** to increase the time it takes to slow the person down; spreading out the impact **D.** All of the above

D. All of the above

______ reduce injuries by providing a cushio that reduces the force on the car's occupants.

Air bags

Would it be better for a crash to be prolonged or an instant impact?

prolonged ## Footnote Increasing the time of the crash reduces the force experienced by the vehicle and occupants.

What is a device that makes work easier by changing the size or direction of force? **A.** power **B.** watt **C.** force **D.** machine

D. machine

What is the work that you do on a machine? **A.** lever **B.** work input **C.** work output **D.** power

B. work input

Which of the following is the comparison of a machine's work output with the work input? **A.** mechanical advantage **B.** force **C.** power **D.** mechanical efficiency

D. mechanical efficiency ## Footnote remember - mechanical efficiency is based on **work**

Which of the following causes machines not to be 100% efficient? **A.** output force **B.** power **C.** friction **D.** input force

C. friction

In which situation is a person doing work on an object? **A.** A student walks while wearing a backpack that weighs 15 N. **B.** A worker holds a box 1 m off the floor. **C.** A man exerts 350 N force on a rope attached to a house. **D.** A school crossing guard raises a stop sign that weighs 10 N.

D. A school crossing guard raises a stop sign that weighs 10 N.

If a barbell weighs 160 N, what other information do you need to calcu.ate how much work it takes to lift it? **A.** the shape of the weights **B.** the weight of the person doing the lifting **C.** how high the barbell is being lifted **D.** the amount of output force

C. how high the barbell is being lifted

If an identical stack of books is lifted the same distance and one person does the job twice as fast, which of the following is done twice as much? **A.** work input **B.** power **C.** work output **D.** efficiency

B. power

What type of energy is stored in bonds?

chemical energy

The force needed to lift an object is equal in size to the gravitational force on the object. How much work is done lifting an object that has a mass of 5 kg a vertical distance of 2 m? **A.** 980 J **B.** 10 J **C.** 24.5 J **D.** 98 J

D. 98 J

A force applied through a distance is known as ____.

work

What are the two conditions that have to be satisfied for work to be done?

1. The applied force must make the object move 2. The movement must be in the same direction as the applied force

True or false: Both work and energy are measured in joules.

True

``` During the ascent phase of a rep of the bench press, the lifter exerts an average vertical force of 1000N against a barbell while the barbell moves 0.8 m upward. ``` How much work did the lifter do to the barbell?

800 J

The rate at which energy is transferred is also known as what?

power

How do you calculate power?

you divide the amount of work done by the time it takes to do that work ## Footnote P = W / t

What unit is power measured in?

watts

True or false: One watt is equal to one joule per second.

True ## Footnote This means that joules per second and watts can be used interchangeably.

A simple machine is a machine that does work with only ____ movement of the machine.

one

List the six types of simple machines.

1. Lever 2. Pulley 3. Wheel and axle 4. Inclined plane 5. Screw 6. Wedge

True or false: The pulley and the wheel and axle are modified levers.

True

What two simple machines are modified inclined planes?

1. Screw 2. Wedge

The ability to do work is also known as ______.

energy

Provide the six different forms of energy.

1. Electrical 2. Chemical 3. Radiant (light) 4. Thermal 5. Nuclear 6. Sound ## Footnote Any form of energy can be converted to another.

The kinetic energy of a moving object depends on the object's _____ and its ________.

mass, velocity (speed)

Provide the kinetic energy equation.

KE = 1/2 mv²

Provide the equation to calculate GPE.

GPE = mgh ## Footnote **gravitational potential energy** (J) = **mass** (kg) x **gravity** (N/kg) x **height** (m)

All forms of energy can be measured in ________.

joules

What does the law of conservation of energy state?

energy cannot be created nor destroyed

Mechanical energy is the sum of the _________ and _________ energies of objects in a system.

kinetic, potential

True or false: The mechanical energy of a system remains constant or nearly constant.

True ## Footnote This happens because as potential energy decreases, kinetic energy increases, and vice versa.

Fuel stores ________ potential energy.

chemical ## Footnote The engine transforms the chemical potential energy of gasoline molecules into the kinetic energy of a moving car or bus.

``` A construction worker is lifting a load of bricks onto a truck. He does 200 J of work in 40 seconds. ``` What is his power output?

5 watts (W)

A roller coaster is at the top of a 72 m hill and weighs 134 kg. The coaster has _________ energy. Calculate it.

* potential * 94,550.4 J

Will a thrown golf ball or a dropped bowling ball hit the ground first when dropped or thrown from the same height on the moon?

Both balls will hit the ground at the same time ## Footnote There is no air resistance on the moon, so gravity is the only determining factor for vertical motion.

# Fill in the missing magnitudes of the unknown forces.

What are the four fundamental forces in the universe?

* Electromagnetic * Strong nuclear force * Weak nuclear force * Gravity

“If gravity causes everything to fall with the same acceleration,” a friend asks, “then why does a crumpled piece of paper fall faster than an uncrumpled one?” How would you answer?

The reason a crumpled piece of paper falls faster than an uncrumpled one is due to air resistance, a friction-like force that opposes the motion of objects as they fall through the air. An uncrumpled paper has more surface area than a crumpled counterpart, so its descent due to gravity is negated more than a crumpled piece.

# Determine the missing information. Fg = 120 N A = 25 m/s² M = ______ F_app = ______

M = 12.24 kg F_app = 306 N

Mr. Hood has a mass of 6871 kg on Earth. What is his weight in Newtons? Explain to him why his weight might be different on another planet like Jupiter.

In Newtons, Mr Hood’s weight is 67,335.8 Newtons. This is due to Earth’s gravitational field, which can be explained with: 9.8 N/kg. On a different planet, the gravitational field may be stronger, like Jupiter, or weaker, like Venus. Weight is just the measure of a gravitational force exerted on an object so it can fluctuate, unlike mass.

Micheal tells Sara he weighs 104 pounds. Sara says she is 487 kilograms. If there are 2.2 pounds in a kilogram, who is heavier?

Sara is heavier