physical science test

Which example identifies a change in motion that produces acceleration

ball moving at a constant speed around a circular track

Speed is the ratio of the distance an object moves to

the amount of time needed to travel the distance

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 trains acceleration is negative

Which distance can be most accurately measured with a ruler?

the width of a book

Vector addition is used when motion involves

(all of the above) direction, speed, velocity

An object moving at 35 m/s takes 5 s to come to a stop. What is the object's acceleration?

-7m/s^2

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

1000

What is the speed of a bobsled whose distance-time graph indicates that it traveled 500 m in 25 s

20 m/s

A car traveled 80 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?

46.4

A ball is rolled uphill a distance of 3 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?

6 meters

Suppose you increase your walking speed from 1 m/s to 8 m/s in a period of 1 s. What is your acceleration?

7 m/s

Displacement vectors of 9 km south, 2 km north, 5 km south, and 5 km north combine to a total displacement of

7km south

A distance-time graph indicates that an object moves 100 m in 5 s and then remains at rest for 6 s. What is the average speed of the object?

9 m/s

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

Acceleration can be described as changes in speed, direction, or both. The ball is moving at a constant speed, but its direction is changing continuously. Because its 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 girl's displacement from home is 1 block east. The pet store is located 1 block east of her home. The girl walked a total distance of 13 blocks.

rate at which velocity changes

acceleration

the slope of a speed-time graph indicates

acceleration

which of the following statements is true

an object at rest has an instaneous accelreation of zero

instantaneous speed is measure

at a particular instant

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

at rest

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 added the vector

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

Objects in free fall near the surface of the Earth experience

constant acceleration

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

front seat of the car

what is an instantaneous

how fast a velocity is changing at a specific instant

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

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 downword

the object that is acceleration may be

slowing down, speeding up, changing,

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

speed

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

traveling around a circular track

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?

zero