A balloon starts rising from the ground with an acceleration of `1.25ms^-2`. After 8 seconds, a stone is released from the balloon. After releasing, the stone will:

Options

A. cover a distance of 50 m till it strikes the ground.
B. have a displacement of 50 till it reaches the ground.
C. reach the ground in 4 seconds.
D. begin to move down instantaneously.

Answer

A, C, D

Explanation

Height of balloon after 8 s:
`h_1=(1)/(2)xx(1.25)xx(8)^2=40`m
Velocity of balloon at this time:
`v_1=1.25xx8=10(m)/(s)`
Further height raised by stone:
`h_2=(v_1^2)/(2g)=(10^2)/(2xx10)=5` m
Distance covered by stone after is released:
`=AB+BC=5+45=50`m
and displacement `=AC=40`m
for stone: from A to C:
`-h_1=v_1t-(1)/(2)gt^2implies-40=10t05t^2`
`impliest^2-2t-8=0implies(t-4)(t+2)=0`
`impliest=4`s.