# Physics Chapter 2

A(n) __________ is a series of images of a moving object that records its position after equal time intervals.

motion diagram

The vector that represents the sum of two vectors is called the __________.

resultant

The length of the position vector on a motion diagram is proportional to the __________.

distance of the object from the origin

In order to use the particle model, the __________ must be __________ moved.

size of the object, much less than the distance

A motion diagram is a series of images of a moving object that records its position after __________.

equal time intervals

Replacing an object in a motion diagram with a single point is called the __________.

particle model

In the particle model, the __________ of the object are (is) ignored.

internal motions

To calculate the distance traveled continuously in a straight line, __________.

subtract final position from starting position

When an object is in motion, its __________ changes.

position

Which of the following statements is true?

The magnitude of a vector is always a positive quantity.

Which of the following correctly describes the displacement of an object that moves from position di to df?

?d = df - di

__________ defines the distance and direction between two positions.

Displacement

How could you locate the position of a sprinter at a particular moment on a motion diagram?

Draw an arrow from the origin to the belt of the sprinter.

The difference between ti and tf is the __________.

time interval

Which of the following is a scalar quantity?

150 km

The horizontal direction in a coordinate system is called the __________.

x-axis

To subtract two vectors, __________.

reverse the direction of the second vector and then add them

A common symbol for the time interval is __________.

?t

In Figure 2-8, If the store were on the other side of your aunt's house, what would your final displacement be if you went from your house to the store to your aunt's?

1.1 km

A quantity that tells you only the magnitude is called a __________ quantity.

scalar

The magnitude of a vector is always __________.

a positive quantity

Displacement has both magnitude and __________.

direction

Two displacements are equal when __________.

the two distances and directions are the same

. Which of the following is not a scalar quantity?

150 km southwest

In Figure 2-8, If the store were on the other side of your aunt's house, what would be your total distance traveled if you went from your house to the store to your aunt's?

0.7 cm

Displacement is a change in __________.

Positioncc

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?

3.7 km south

The vertical direction in a coordinate system is called the __________.

y-axis

The __________ is the point at which both variables in a coordinate system have the zero value.

origin

The distance and direction between the final position and the starting position is the __________ .

displacement

A(n) __________ tells you where the zero point of the variable you are studying is located and the direction in which the values increase.

coordinate system

In a position-time graph, t represents __________.

time

On a position-time graph, rise = __________.

?d

On a position-time graph, run = __________.

?t

You are at a friend's house who lives 10 km north of your house. You drive north from there at a constant speed of 35 mph toward the pizza shop and arrive there 10 minutes later to pick up your pizza. How far from your house are you?

20 km

You drive a car for 2.0 h at 60 km/h, then for another 3.0 h at 85 km/h. What is your average velocity?

75 km/h

Based on the graph of Figure 2-21, what is the object's velocity at t = 4 s?

-5m/s

The slope of the line tangent to the curve on a position-time graph at a specific time is the __________.

instantaneous velocity

The magnitude of velocity is __________.

speed

A bicycle rider travels 15 km in 1.25 hours. What is the rider's average speed?

12 km/h

If a runner maintains a constant speed of 12.0 km/h, how long will it take him to complete a marathon race of 26.2 miles?

3.52 hr

The __________ is the ratio of the total distance traveled to the time interval.

average speed

Looking at Figure 2-20, at what time would the first picture of the joggers be most likely to have occurred?

-1 s

You and a friend leave school at the same time. You drive at a constant 55 km/h and your friend drives 7.0�101 km/h. How long does it take each car to reach a mall that is 25 km from the school?

you: 27 minutes, your friend: 22 minutes

You drive a car for 3.0 h at 97 km/h, then for another 3.0 h at 72 km/h. What is your average velocity?

85 km/h

You and a friend each walk 8.0 km. You walk at 6.4 km/h; your friend walks 8.1 km/h. How long will your friend wait for you at the end of the walk?

15 min

Based on the graph of Figure 2-21, where would the object be at t = 7 s?

-15 m

In Figure 2-20, if the blue jogger were ahead of the red jogger at t = 0 s, but they both had the same velocities as in the text, how (if at all) would the graph change?

The slopes of the lines would remain the same, but the blue jogger's line would cross the y-axis above zero.

Which of the following equations can be used to find the position of an object moving at constant velocity?

d = df + vt