Question

Which of the following motions does not represent a combined motion?

• A. A ball rolling down on an inclined plane
• B. A box siding down on an inclined plane
• C. The motion of the Earth
• D. The motion of the wheels of a bullock-cart​

Answer 1

The correct option is B A box siding down on an inclined plane

We know that a body can have multiple types of motion at a given instant, in the question it is asked to find the motion which is not associated with the multiple types of motion.

• The wheels of a moving bullock-cart undergo two types of motion mainly rectilinear and rotational. Rectilinear because wheels are moving along the straight line and rotational because wheels are rotating around the fixed axis.
• The motion of the Earth is rotational around its own axis, circular motion around the Sun and periodic as these motions are repeated after a fixed interval of time.
• A box sliding down on an inclined plane undergoes a rectilinear motion only.
• A ball rolling down on an inclined plane undergoes rotational and rectilinear motion. Rectilinear because the ball is moving along a straight line and rotational because it is rotating about a fixed axis.