C4 Terms

Question 1

Mechanics

Answer 1

The scientific study of forces and motion. It consists of kinematics, dynamics and statics.

Question 2

Kinematics

Answer 2

The science of describing how things move. It involves the measurements and calculations of position, time, velocity, acceleration, and displacement within a reference frame.

Question 3

Dynamics

Answer 3

The study of how forces affect an object’s motion. Based on Newton’s 3 laws of motion.

Question 4

Statics

Answer 4

The description of how stationary objects react to pushes and pulls.

Question 5

System

Answer 5

Part of the universe under study separated from its surroundings by an actual or imaginary boundary.

Question 6

Surroundings

Answer 6

Everything outside a system’s boundary.

Question 7

Frame of reference

Answer 7

The geometric space containing the reference point and coordinate axes from which a person observes or measures position and movement.

Question 8

Coordinate axis

Answer 8

An imaginary line that contains an origin as a point of reference and is marked off in distance units.

Question 9

Interval

Answer 9

A span of time during which a phenomenon is observed, calculated by subtracting the initial time from the final time. Always a positive number.

Question 10

scalar

Answer 10

Any measurable property, represented by an italicized symbol, that can be completely described by a single piece of information. It can be either positive, negative, or zero. Includes volume, temperature, time and mass measures.

Question 11

Vector

Answer 11

A measurable quantity, represented by a bold symbol (or a 1/2 arrow above the scalar symbol), that requires two pieces of information to fully describe it

Question 12

distance

Answer 12

A positive scalar quantity representing the linear dimension a moving object covers during a time interval. It also may be the magnitude of displacement.

Question 13

displacement

Answer 13

A vector quantity that describes the net distance and direction of motion. It is represented graphically by a vector arrow whose tail is at the starting point of motion and whose tip is the ending point.

Question 14

magnitude

Answer 14

The size of any quantity expressed as a positive number in appropriate units.

Question 15

speed

Answer 15

A scalar quantity that measures the rate of motion of a system. It may also be the magnitude of velocity.

Question 16

average speed

Answer 16

The average rate of motion over a time interval that accounts for variations in speed. It is a positive scalar quantity.

Question 17

Velocity

Answer 17

The vector quantity of the rate of displacement of a system or it can be described as speed in a given direction.

Question 18

acceleration

Answer 18

The rate of change of the speed or velocity of a system during a time interval. It can either be a vector or scalar quantity.

Question 19

What is mechanics the study of?

Answer 19

forces and motion

Question 20

Who tried to explain motion by determining why things move?

Answer 20

Aristotle

Question 21

The early Greek philosopher Aristotle tried to explain _______ things moved.

Answer 21

why

Question 22

Galileo proposed that we study _______ things move before we conclude ________ things moved.

Answer 22

how

why

Question 23

________ proposed that we study how things moved before we conclude why they move.

Answer 23

Galileo

Question 24

________ is generally given credit as the pioneer in the modern study of mechanics.

Answer 24

Newton

Question 25

Modern physics has divided the study of mechanics into what three parts?

Answer 25

kinematics dynamics statics

Question 26

Which branch describes how things move?

Answer 26

kinematics

Question 27

What is the branch of mechanics that describes why things move.

Answer 27

Dynamics

Question 28

A system of reference points from which the position and motion of an object can be determined is referred to as the _______________________.

Answer 28

Frame of reference

Question 29

What kind of quantities only have size?

Answer 29

scalars

Question 30

Name some scalar quantities

Answer 30

temperature, mass, time, volume, density, length, area, speed, energy.

Question 31

Things that have ______ as well as ________ are called vector quantities.

Answer 31

size | direction

Question 32

Name some vector quantities.

Answer 32

velocity, force, momentum, position in space, acceleration

Question 33

The _______ moved in a given ________ is called displacement.

Answer 33

distance | direction

Question 34

Distance and displacement are identical quantities. (T or F)

Answer 34

F

Question 35

Velocity and speed are the same. (T or F)

Answer 35

F

Question 36

Speed in a specified direction is called __________.

Answer 36

Velocity

Question 37

Distance divided by time defines ________.

Answer 37

speed

Question 38

Displacement divided by time defines _______.

Answer 38

Velocity

Question 39

Imagine that Bob ran around his school starting at the front doors. The total distance from start to finish in front of his school was 700 m. It took Bob 100 seconds to complete the run. What was his average speed? What was his average velocity?

Answer 39

speed–7 m/s | velocity–0 m/s (his displacement was zero)

Question 40

Acceleration is the technical name for speed. (T or F)

Answer 40

F

Question 41

The rate of change of velocity in a given time interval is called __________.

Answer 41

acceleration

Question 42

A negative change in acceleration is called_________.

Answer 42

Deceleration

Question 43

What is deceleration?

Answer 43

a negative change in acceleration

Question 44

Can a car traveling cross–country have a constant velocity?

Answer 44

no. speed limits change often and stop lights and bathroom brakes interfere and disrupt your velocity.

Question 45

Spatial

Answer 45

Describes something relating to or having the properties of space. 3 spatial dimensions - length, width, height.

Question 46

Why are frames of reference important?

Answer 46

They determine how motion will be described.

Question 47

What is the correct reference frame for a given situation?

Answer 47

In motion , no single reference frame is more correct than another.

Question 48

What is best reference frame?

Answer 48

The frame that is most useful or makes the study of that motion easiest.

Question 49

In physics, how is a system used?

Answer 49

A system helps to identify what factors must be taken into account in experiments and any scientific models developed.

Question 50

Why are frames of reference important to the study of motion in physics?

Answer 50

They "anchor" observations and act as a landmark.

Question 51

What is correct frame of reference for a given situation?

Answer 51

In motion, no single reference frame is more correct than another.

Question 52

What is the best frame of reference?

Answer 52

The one that is the most useful or in which the study of that motion is easiest.

Question 53

You're riding in an accelerating car that passes another car. What type of reference frame produces this kind of observed motion?

Answer 53

Accelerated reference frame

Question 54

Three types of reference frames

Answer 54

Fixed reference frame Accelerated reference frame Rotational reference frame

Question 55

Motion in a straight line, in 2 or 3 dimensions it is generally acceptable to use a ______ ______ frame in which the system of interest moves.

Answer 55

Fixed reference frame

Question 56

When studying a system that revolves, it is often more convenient to choose an accelerated reference frame in which the rotating object and its axis are stationary. This is called a ________ _________ frame.

Answer 56

Rotational reference frame. It permits analysis of the pushes and pulls that cause the circular motion and the motions of other systems relative to the rotating system.

Question 57

(T/F) The fact that one's point of view affects one's observations applies to many aspects of scientific investigation, including motion.

Answer 57

True

Question 58

Continuum

Answer 58

Unbroken expanse or series.

Question 59

What is another name for the magnitude of the velocity vector?

Answer 59

Speed

Question 60

How many position coordinates are required to identify the position of a system undergoing 1 dimensional motion?

Answer 60

1

Question 61

What symbol should you use to identify a system's position in one-dimensional motion?

Answer 61

x

Question 62

What quantity does the formula for speed provided?

Answer 62

Average speed

Question 63

Acceleration can occur if velocity changes _________, ___________ or both.

Answer 63

magnitude | direction

Question 64

(T/F)Negative acceleration always means a system is slowing down.

Answer 64

False. Negative acceleration means that an acceleration is occurring in the negative direction of the coordinate system.

Question 65

Contrast views of Greeks and scientists after Galileo & Newton.

Answer 65

4.1 Greeks - matter behaved in mysterious ways. After Galilieo/Newton, scientists observe how things move and then describe their motion with math.

Question 66

How does kinematics differ from dynamics?

Answer 66

kinematics - how things move, dynamics - what makes them move.

Question 67

A skier is schussing down a snowy slope. Describe everything that is part of the skier-system.

Answer 67

Jacket, snowpants, skis, poles, helmet, goggles, boots, gloves.

Question 68

On a flight simulator game. What is the reference frame for the computer image?

Answer 68

The cockpit.

Question 69

What evidence do we have that time began at creation?

Answer 69

Time began at creation. Gen 1:1

Question 70

A vector quantity can be represented by a stylized arrow. How does this symbol represent a vector quantity.

Answer 70

The length of the vector arrow indicates the size of the scalar value and the direction the arrow points is the direction of the vector

Question 71

When would actual distance traveled = the magnitude of a system's displacement?

Answer 71

The displacement and distance traveled are = when an object has traveled in a straight line in one direction between two points.

Question 72

Explain why speed is a rate?

Answer 72

It compares the change in the value of a quantity in a certain span of time.

Question 73

Explain why acceleration is a rate?

Answer 73

It is the rate of change of the speed or velocity during a given time interval.

Question 74

What instrument displays the instantaneous speed of a car (the speed a car is moving at an instant in time)?

Answer 74

The speedometer.

Question 75

What is significant about the sign of velocity in one dimensional motion?

Answer 75

It indicates the direction the objects are moving.

Question 76

What kind of coordinate system is required to describe most real-world motion? Why?

Answer 76

Two and three dimensional motion. | Most real world motion occurs in these.

Question 77

(T/F) In mechanics it is vital to understand how to measure motion before you try to understand the causes of motion.

Answer 77

True.

Question 78

(T/F)When studying the motion of a thrown ball, the system is the ball and the hand that throws it.

Answer 78

True.

Question 79

(T/F)The weather-vane on top of a barn measures the wind vector.

Answer 79

True.

Question 80

(T/F) Position in a 1 dimensional requires only a single number.

Answer 80

True.

Question 81

(T/F) The magnitude of -15.0 m/s is 15.0 m/s

Answer 81

True.

Question 82

(T/F) * The instantaneous speed of a car must equal it's average speed at least once during a trip.

Answer 82

True.

Question 83

(T/F) In most cases of motion, scientists try to avoid measuring velocities because it complicates measuring the data.

Answer 83

False.

Question 84

(T/F) Increasing speed always indicates positive acceleration and decreasing speed always indicates negative acceleration.

Answer 84

False.

Question 85

(T/F) Acceleration is the rate of change of the rate of change of position.

Answer 85

True.

Question 86

(T/F) The definition of distances, displacement, speed, velocity and acceleration are the same in 1,2,or 3 dimensional coordinate systems.

Answer 86

True.