Chapter 11: Motion

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

• the side of the road.

• a pedestrian on the corner ahead.

• the front seat of the car.

• the wheels of the car.

A person drives north 3 blocks, then turns east and drives 3 blocks. The driver then turns south and drives 3 blocks. How could the driver have made the distance shorter while maintaining the same displacement?

• by driving east 3 blocks from the starting point

• by driving north 1 block and east 4 blocks

• by driving west 3 blocks from the starting point

• by driving back to the starting point by the same route

Displacement vectors of 1 km south, 3 km north, 6 km south, and 2 km north combine to a total displacement of

• 2 km.
• 3 km

• 12 km

• -2 km

Speed is the ratio of the distance an object moves to

• the amount of time needed to travel the distance.

• the direction the object moves.

• the displacement of the object.

• the motion of the object.

A car traveled 88 km in 1 hour, 90 km in the next 2 hours, and then 76 km in 1 hour before reaching its destination. What was the car’s average speed?

• 74.5 km/h
• 63.5 km/h

• 84.67 km/h

A distance-time graph indicates that an object moves 100 m in 4 s and then remains at rest for 1 s. What is the average speed of the object?

• a. 50 m/s

• b. 25 m/s

• c. 20 m/s

• d. 100 m/s

Vector addition is used when motion involves

• a. more than one direction.

• b. more than one velocity.

• c. more than one speed.

• d. all of the above

Which example identifies a change in motion that produces acceleration?

• a. a speed skater moving at a constant speed on a straight track

• b. a ball moving at a constant speed around a circular track

• c. a particle moving in a vacuum at constant velocity

• d. a vehicle moving down the street at a steady speed

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

• a. increasing speed while traveling around a curve

• b. an object at rest

• c. traveling around a circular track

• d. an object in free fall

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

• a. 30 m/s²

• b. –30 m/s²

• c. –6 m/s²

• d. 6 m/s²