Question

A body is moving in a straight path. Then,

• A. its instantaneous speed is equal to its instantaneous velocity.
• B. its average speed is equal to its average velocity.
• C. its acceleration is equal to a change in its velocity.
• D. Both (a) and (b).

Answer 1

The correct option is D

Both (a) and (b).

Step 1: Explanation for the correct answer

1. When a body is moving in a straight-line path, this means that the motion of the body is in a particular direction.
2. We know that instantaneous speed is the speed of an object at a particular point in time and the instantaneous velocity considers the velocity of the object at a certain point in time.
3. For a body in a straight-line path, both the instantaneous speed and instantaneous velocity will be the same.
4. Average speed is the ratio of total distance covered to the total time taken by the body whereas average velocity is the ratio of displacement to the time taken by the body.
5. In this case(Straight-line motion of the object), the distance and displacement will be the same so the value of average speed and average velocity will be the same.

Hence, the correct answer is (D).