A tennis ball dropped on a barizoontal smooth surface , it because back to its original postion after hiting the surface the force on the bell during the collision is propertional to the length of compression of the bell . Which one of the following skethes desches discribe the variation of its kinetic energy `K` with time `1` mass apporiandly ? The figure as only illistrative and not to the scale .

Options

A.
B.
C.
D.

Answer

B

Explanation

Dring fall, `v = 0 + g t`
`KF = (1)/(2)mv^(2) = (1)/(2)m (g t)^(2)`
`KE prop t^(2)`, so graph is upward parabola.
During collision. KE will decrease in compression and increase in reformation.
Finally, During going up KE will decrease.