Question

A ball is thrown upwards from the bottom of a fixed chamber of height $20\text{m}$ with a speed of $10\text{m/s}$. The interior of the chamber has no gravity. The ball strikes the ceiling of the chamber and rebounds. After $6\text{seconds}$, gravity is reintroduced in the chamber. The movement of the ball gradually slows down over time and the ball comes to rest. Which of the following is the correct displacement vs time graph for the movement of the ball inside the chamber?

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

When there is no gravity in the chamber, then the ball maintains the initial uniform velocity throughout its motion. Hence the graph until $6\text{seconds}$ will be a straight line.

After $6\text{seconds}$, gravity is introduced into the chamber. Under the action of gravity, the ball slows down as it moves up and accelerates as it comes down. Hence the displacement vs time graph will be a parabola after $6\text{seconds}$.

Hence the correct option is (c).