Chapter 11 Review

Distance is a measure of length. What information does displacement give in addition to distance?

Direction

A person walks 1 mile every day for exercise, leaving her front porch at 9:00 am. and returning to her front porch at 9:25 am. What is the total displacement of her daily walk?

0

If you ride your bike at an average speed of 4 km/h and need to travel a total distance of 28 km, how long will it take you to reach your destination? Show your work.

28km / 4km/h = 7 hours.

Which example identifies a change in motion that produces acceleration?

a ball moving at a constant speed around a circular track

A constant slope on a distance-time graph indicates ___ speed.

constant

The velocity of an object moving in a straight line changes at a constant rate when the object is experiencing ___

constant acceleration

Objects in free fall near the surface of the Earth experience

constant acceleration.

Accelerated motion is represented by a(an) ___ line on a distance-time graph.

curved

What is the most appropriate SI unit to express the speed of a cyclist in the last leg of a 10-km race?

km/h

Vector addition is used when motion involves

More than one direction, more than one speed, more than one velocity.

The motion of an object looks different to observers in different ___.

frames of reference

Freely falling objects accelerate at 9.8 m/s2 because the force of ___ acts on them.

gravity

What is instantaneous acceleration?

how fast a velocity is changing at a specific instant

A car's speedometer measures ___

instantaneous speed

An object that is accelerating may be

slowing down, changing direction, and gaining speed.

The slope of a line on a distance-time graph is

speed

Speed is the ratio of the distance an object moves to

the amount of time needed to travel the distance.

A passenger in the rear seat of a car moving at a steady speed is at rest relative to

the front seat of the car.

Which distance can be most accurately measured with a ruler?

the width of the book.

Two or more velocities add by ___

vector addition

Displacement and velocity are examples of ___ because they have both magnitude and direction.

vectors

The acceleration of a moving object is calculated by dividing the change in ___ by the time over which the change occurs.

velocity

An object moving at 30 m/s takes 5 s to come to a stop. What is the object's acceleration?

-6 m/s^2

A distance-time graph indicates that an object moves 100 m in 4 s and then remains at rest for 6 s. What is the average speed of the object?

10 m/s

One kilometer equals 1000 meters. What does the prefix kilo- mean?

1000

During a race, a runner runs at a speed of 6 m/s. 2 seconds later, she is running at a speed of 10 m/s. What is the runner's acceleration? Show your work.

10m/s - 6m/s / 2 sec the runner's acceleration is 2m/s^2

Displacement vectors of 4 km south, 2 km north, 5 km south, and 5 km north combine to a total displacement of

2 km south

Suppose you increase your walking speed from 1 m/s to 3 m/s in a period of 1 s. What is your acceleration?

2 m/s^2

What is the speed of a bobsled whose distance-time graph indicates that it traveled 100 m in 25 s?

4 m/s

A ball is rolled uphill a distance of 5 meters before it slows, stops, and begins to roll back. The ball rolls downhill 9 meters before coming to rest against a tree. What is the magnitude of the ball's displacement?

4 meters

A car traveled 60 km in 2 hours, 84 km in the next 1 hour, and then 68 km in 2 hours before reaching its destination. What was the car's average speed?

42 km/h

A distance-time graph indicates an object moves 20 km in 4 h. The average speed of the object is ___ km/h.

5

A child rolls a ball 6 m across a room. The ball hits the wall and rolls halfway back toward the child. Using vector addition, calculate the ball's displacement.

6m + (-3m) = 3m

Which of the following statements is true?

An object at rest has an instantaneous acceleration of zero.

What are two types of speed that can be used to describe the motion of a car driving on the highway?

Average speed and instantaneous speed

A river current has a velocity of 5 km/h relative to the shore, and a boat moves in the same direction as the current at 5 km/h relative to the river. How can the velocity of the boat relative to the shore be calculated?

By adding the vectors

___ is how fast a velocity is changing at a specific instant.

Instantaneous acceleration

What is the SI unit best suited for measuring the height of a building?

Meters

Explain how velocity is different from speed.

Speed is equal to the distance traveled divided by the time required to cover the distance. Velocity describes both speed and direction of motion.

What types of changes in motion cause acceleration?

Speed, direction, or both.

Picture a ball traveling at a constant speed around the inside of a circular structure. Is the ball accelerating? Explain your answer.

The acceleration can be described as changes in speed, direction, or both. The ball is moving at a constant speed, but it's direction is changing continuously. Because it's direction is changing, the ball is experiencing continuous acceleration.

A girl walks from her home to a friend's home 3 blocks north. She then walks 2 blocks east to the post office, 1 block north to the library, and 1 block east to the park. From the park, she walks 2 blocks west to the movie theater. After the movie, she walks 4 blocks south to the pet store. What is the girl's displacement from her starting point to the pet store? Where is the location of the pet store in relation to her home? Calculate the distance she walked in blocks.

The pet store is one block relative west from the pet store. The displacement is one block east. The girl walked a total distance of 13 blocks.z

What is the significance of the slope in a distance-time graph?

The slope is the change in distance divided by the change in time, which gives speed.

Bus A travels 275 m in 13 s. Bus B travels 290 m in 13 s. Both vehicles travel at constant speed. How do the distance-time graphs for these two speeds differ?

The slope of the line representing Bus B is steeper than the line representing Bus A.

A train approaching a crossing changes speed from 25 m/s to 10 m/s in 240 s. How can the train's acceleration be described?

The train's acceleration is negative.

Which example describes constant acceleration due ONLY to a change in direction?

Traveling around a circular track

A moving object does not ___ if its velocity remains constant.

accelerate

The rate at which velocity changes is called ___.

acceleration

The slope of a speed-time graph indicates ___?

acceleration

Instantaneous speed is measured

at a particular instant

A horizontal line on a distance-time graph means the object is

at rest

v=d/t is the equation that defines ___

average speed

A person drives north 6 blocks, then turns west, and drives 6 blocks. The driver then turns south and drives 6 blocks. How could the driver have made the distance shorter while maintaining the same displacement?

by driving west 6 blocks from the starting point

Because its ___ is always changing, an object moving in a circular path experiences a continuous change in velocity.

direction

The difference between speed and velocity is that velocity indicates the ___ of motion and speed does not.

direction

The direction and length of a straight line from the starting point to the ending point of an object's motion is ___.

displacement

The SI unit for measuring ___ is the meter.

distance

A speed-time graph shows that a car moves at 10 m/s for 10 s. The car's speed then steadily decreases until it comes to a stop at 30 s. Which of the following describes the slope of the speed-time graph from 10 s to 30 s?

linear, sloping downward

Speed is measured in units of ___

meters per second

A car that increases its speed from 20 km/h to 100 km/h undergoes ___ acceleration.

positive

The sum of two or more vectors is called the ___

resultant vectors