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. (a) cover a distance of ` 40 m`
B. (b) have displacement of ` 50 m`
C. (c ) reach the ground in `4` seconds `
D. (d) beging to move downward after being released.

Answer

C

Explanation

Taking upward motion fo balloon for `8` second , we have
` u= 0, a = 1.25 m/ss^2 , t= 8 sec, v= ? , S=?`
As ` v=u + at = 0 + 1.25 xx 8 10 m//s`
` S = ut +1/2 at^2 = 0 1/2 xx `1.25 xx 8^@ = 40 m`. ltBrgt Taking downward motion fo released stone from balloon at height ` 40 m` we have,
` u=- 10 m//s , a = 10 m//s^2, S= 40 m , t= ?`
or ` t^2- t-8 8 =0`. On solig , ` t= 4 s`.