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September 18, 2014

September 18, 2014

Posted by **Lanny** on Tuesday, June 4, 2013 at 1:27pm.

B. when the object reaches its destination.

C. at a particular instant.

D. over the duration of the trip.

2. 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?

A. 4 meters

B. 9 meters

D. 45 meters

3. What is instantaneous acceleration?

A. how fast a speed is changing at a specific instant

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

C. how fast a direction is changing at a specific instant

4. An object that is accelerating may be

A. slowing down.

C. changing direction.

D. all of the above

5. Speed is the ratio of the distance an object moves to

A. the amount of time needed to travel the distance.

B. the direction the object moves.

C. the displacement of the object.

6.Which example identifies a change in motion that produces acceleration?

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

7. 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?

A. The train’s acceleration is positive.

C. The train will come to rest in 6 minutes.

D. The train’s acceleration is negative.

8. 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?

A. by subtracting the river current vector from the boat’s velocity vector

C. by multiplying the vectors

D. by adding the vectors

- Physical Science -
**Elena**, Tuesday, June 4, 2013 at 3:29pm1C. at a particular instant.

2A. 4 meters

3B. how fast a velocity is changing at a specific instant

4D. all of the above

5A. the amount of time needed to travel the distance.

6D. The train’s acceleration is negative.

7D. by adding the vectors

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