Question

Assertion: When final position of a body coincides with its initial position, the body is surely at rest. Reason: This is because distance is scalar and displacement is vector​

Answer 1

Answer:

The assertion is false but the reason is true

It is not necessary that if the final position of a body coincides with it's initial position, so the body is at rest, as displacement (straight line distance from the initial position) is zero when the object goes back to the initial position, but it isn't necessary that the distance be zero. The body might have started from the position, travelled a distance (the path traced by a body), and reached back to the initial position, which is also it's final position. Therefore, distance might not be zero and so we cannot be sure that the body is at rest. Yet, displacement will be zero.

The reason for the above answer is that distance is a scalar quantity (it only has magnitude), whereas displacement is a vector quantity (it has magnitude and direction (straight line) as well). So direction doesn't affect the distance travelled, but it does affect the displacement, which can be seen in the above case.

HOPE IT HELPS;)

peace!