Intro, Motion & Energy Flashcards
The tendency of a moving object to remain in unchanging motion in the absence of an unbalanced force is called _______
inertia
The newton is a unit of ______
force
Gravity is an attractive force between ___ _______ __________
all objects everywhere
Everything that happens in the universe can be traced to interactions of ____ ___________ ______
four fundamental forces
What are the four fundamental forces?
gravitational
electromagnetic
weak
strong
If a block of iron is transported to the moon, what changes: mass, weight, both, or neither
weight
Neglecting air resistance, a ball in freefall will have ________ ____________ & __________ _____
constant acceleration & increasing speed
50 kg is about how many newtons?
500
Neglecting air resistance, if a ball falls for 2 seconds, how far did the ball fall?
19.6 meters
Suppose that a rock is swinging in a circle when some string is let out so that the length doubled as the same speed is maintained. The force now exerted on the string is _____ as great as before
half
After being released, a ball dropped straight down from a bridge would have an acceleration of
9.8m/s^2
A gun is aimed perfectly at an apple hanging from a tree. The instant the gun is fired the apple falls to the ground. Will the bullet hit the apple? Explain reasoning
Yes, it will because all objects fall at the same rate meaning the bullet and the apple are both falling at the same time
For an object moving across an icy surface, if you double the mass of an object while the (unbalanced) force remains constant, what happens?
The object will move at half the speed
True or false: Certain professional football players can throw a football so fast that it moves horizontally in a flat trajectory.
False because no matter how hard the ball is thrown, it will still fall at 9.8m/s^2
True or false: When you roll a ball across the floor, it eventually comes to a stop because you are no longer exerting a force on it.
False: No force is required to keep an object in motion. The ball comes to a stop because it is being acted upon by other forces such as friction
True or false: An object accelerates when it slows or its direction of movement changes.
True
True or false: Newton’s second law states that if an unbalanced force acts on an object, it will move at constant velocity.
False
True or false: The reason a moving object slows down is that its force of motion gradually runs out.
False: No force is required to keep an object in motion. The ball comes to a stop because it is being acted upon by other forces such as friction
True or false: The momentum of an object remains the same unless an unbalanced force acts on it.
true
How many centimeters are in one meter?
100
How many millimeters are in one meter?
1,000
How many decimeters are in one meter?
10
True or false: The density of a 100 g piece of iron is twice as great as the density of a 50 g piece of iron.
False: If the volume of both pieces is equal, then yes, this would be true, but since no volume measurements have been given, then it is impossible to say which has greater density.
True or false: The property of mass is a measure of how heavy an object is
False: Weight is a measure of how heavy an object is. It takes gravity into account.
True or False: The symbol “∆” is used to refer to an object’s density.
False: This symbol represents change. The symbol for density is the Greek letter rho (which looks like a lowercase p).
What is a referent?
A referent is a familiar object one can use to describe the property of an object
What is the proportional relationship between the number of cookies in the cookie jar and the time you have been eating the cookies?
inverse
A 1-cm3 piece is removed from a very large lump of modeling clay with a volume of over 100,000 cm3. Which piece has the greatest density?
The density is the same. The small piece has a smaller volume, but it also has a smaller mass.
When a ice cube with a certain weight melts, will the resulting weight of water be greater, less, or equal?
equal
When a ice cube with a certain weight melts, will the resulting volume of water be greater, less, or equal?
less
Is ice more or less dense than water?
less
The property of volume is a measure of what?
how much space the object occupies
A statement describing a relationship that is observed in nature to occur consistently time after time is called what?
scientific law
Quantities, or measured properties, that are capable of changing values are called what?
variables
What is the metric standard unit for mass?
kilogram
If the volume of an object increases, but the mass remains the same… will the density increase, decrease, or remain the same?
decrease
What is the density of iron if 5.0cm3 has a mass of 39.5g?
7.9
If ice has a density of 0.92 g/cm3, what is the volume of 5,000g of ice?
5,400 cm3
The energy an object has because of its position is called what?
potential energy
True or false: Energy is conserved when a moving object slows to a stop.
True. Even though the total amount of energy in the universe remains constant, energy form does change, so this does conserve usable energy.
A spring-loaded paper clamp exerts a force of 2 N on 10 sheets of paper it is holding together. Is the clamp doing work as it holds the papers together?
No because there is no motion involved
Kinetic energy is described as:
the energy of motion
The formula for finding potential energy is PE=mgh. What do each of these variables mean?
M = mass G = acceleration of gravity (or 9.8m/s^2) H = height from the ground
A car is moving straight down a highway under ideal conditions. What factor has the greatest influence on how much work must be done on the car to bring it to a complete stop?
how fast the car is moving
The solar technology that is today contributing about as much energy as moving water is _______.
biomass
Which form of energy does not require matter for traveling through space?
radiant
What is the basic problem today with using solar cells as a major source of electricity?
manufacturing cost
What is pseudoscience?
misleading and often absurd claims of scientific results
What two men are known as the beginners of modern science?
Galileo & Newton
What is a concept?
a generalized mental image of something
What are the five types of energy?
Mechanical, Radiant, Nuclear, Chemical, Electrical
What is the difference between speed and velocity?
Velocity describes speed and direction
What does this equation mean?: D=1/2AT^2
This is the equation for falling objects or vertical motion: Distance (D) = 1/2 acceleration (A) multiplied by Time (T) squared
