1.Instantaneous speed is measured



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

1. Instantaneous speed is measured at a particular instant (Option C). To find the instantaneous speed of an object, you need to measure its speed at a specific moment or instant in time, rather than over the duration of the entire trip or when it reaches its destination.

2. The magnitude of the ball's displacement can be calculated by finding the difference between the distance it travels uphill and the distance it travels downhill. In this case, the ball rolls uphill for 5 meters and then rolls downhill for 9 meters. The magnitude of its displacement is the absolute value of the difference between these distances, which is 9 - 5 = 4 meters. Therefore, the answer is A. 4 meters.

3. Instantaneous acceleration is the rate at which velocity changes at a specific instant (Option B). It measures how fast an object's velocity is changing at a particular moment in time. To calculate instantaneous acceleration, you need to determine the change in velocity over an infinitesimally small time interval.

4. An object that is accelerating can be both slowing down and changing direction (Option D). Acceleration refers to any change in an object's velocity, which includes both changes in speed (slowing down or speeding up) and changes in direction. So, when an object accelerates, it can experience both slowing down and changing direction simultaneously.

5. Speed is the ratio of the distance an object moves to the amount of time needed to travel that distance (Option A). It is a measure of how quickly an object covers a certain amount of distance. To calculate speed, you divide the distance traveled by the time it takes to travel that distance.

6. A change in motion that produces acceleration is a ball moving at a constant speed around a circular track (Option B). While the ball's speed remains constant, its velocity constantly changes direction due to the circular path. Since acceleration is defined as the rate of change of velocity, the ball's change in direction produces acceleration.

7. The train's acceleration can be described as negative (Option D). This is because the train is going from a higher speed (25 m/s) to a lower speed (10 m/s), which indicates a decrease in velocity. As acceleration is defined as the rate of change of velocity, a decrease in velocity corresponds to negative acceleration.

8. The velocity of the boat relative to the shore can be calculated by subtracting the river current vector from the boat's velocity vector (Option A). Since the boat is moving in the same direction as the river current, you subtract the magnitude and direction of the river current from the boat's velocity vector to determine the boat's velocity relative to the shore.

1C. 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