An elevator without a ceiling is ascending up with an acceleration of `5 ms^-2.` A boy on the elevator shoots a ball in vertical upward direction from a height of 2 m above the floor of elevator. At this instant the elevator is moving up with a velocity of `10 ms^-1` and floor of the elevator is at a height of 50 m from the ground. The initial speed of the ball is `15 ms^-1` with respect to the elevator. Consider the duration for which the ball strikes the floor of elevator in answering following questions. (`g=10 ms^-2`)
3. Displacement of ball with respect to ground during its night would be

Options

A. 32.64 m
B. 31.86 m
C. 52 m
D. 30.64 m

Answer

B

Explanation

b. From the figure, it is very clear that distance travelled by the
ball is
`H = h + [h-(s_1-2)] = 2h - s_1 + 2 = 31.86m`.