The childern are trying to shoot a marble into a marble into a small box using a spring loaded gun that fixed on a table and shoots horizontally from the edge of the table. The centre of the box is a horizontal distance `5m` from the edge of the table. The first child compresses the spring a distance `2cm` and finds that the marble falls short of its target by a horizontal distance `3m`. By what distance `x` should the second child compress the spring to score a direct hit on the box?

Options

A. `15cm`
B. `10cm`
C. `4cm`
D. `5cm`

Answer

D

Explanation

`(1)/(2)m u^(2)=(1)/(2)kx^(2)rArrupropx`
`R=usqrt((2h)/(g))propupropxrArr(2)/(5)=(2)/(x)rArrx=5cm`