Question

The average velocity and the average speed would remain the same for:

• A. A train travelling between two cities on a linear track
• B. A toy train making a round trip on a circular track
• C. A car travelling on a straight road
• D. A girl swimming linearly in a pool.

Answer 1

Answer: (A), (C), (D)

The correct options are
A A train travelling between two cities on a linear track
C A car travelling on a straight road
D A girl swimming linearly in a pool.

For average velocity and average speed to be same, the distance and displacement of the body should be the same in the given time interval.

• A train travels in a straight line on a linear track which is the smallest distance between the initial and final positions. So its distance and displacement are the same.
• Similarly, for a car moving in one direction on a straight road, and for a girl who swims straight from one end to the other in a swimming pool, the distance and displacement are going to be the same.

But, for a toy train making a round trip on a circular track, the displacement will be zero, whereas the distance is not.