Question

Fill in the blank with the correct word:
When a body is in translational motion, all its parts move …………. (equal/unequal) distances in equal time.

Answer 1

Hint : A particle is said to have undergone translational motion when it is shifted from one position to another. Hence, a rotational motion is non translational motion. An object must not change its orientation about a fixed axis on itself for it to undergo translation

Complete step by step answer
Usually, for a point particle (a particle with no spatial dimension i.e. no volume), when it is shifted from a position or changes location in space, it is said to have undergone translational motion.
However, for objects with spatial dimension, there is an added condition that for translational motion to take place, the object orientation about a point in itself must be constant throughout the motion. Hence, rotational motion is not translational.
Now an object can be said to be made of point particles combined together, hence, when the object is translated, then all parts (or all points) are equally moved in the same direction, tracing out the same path or trajectory. They would also start and end at the same time, having the same velocity, and acceleration.
Hence, when a body is in translational motion, all parts move equal distances in equal times

Note
For clarity, rotational motion is not classified as a translational motion because if rotation is involved in a linear motion for an example (like a rolling ball), all points will not trace out equal trajectories. The point at the circumference will trace out a cycloid with a larger radius, while the points at the centre will trace out a purely linear motion.