Question

a balloon is moving vertically upward with a velocity of 4m/s.when it is at a height of h,a stone is dropped from it.if it reaches ground in 4s,the height of the balloon,when the stone is released,is (g=9.8m/s×s).​

Answer 1

Answer :

• height of balloon when stone is released from it is 62.4 metres.

Explanation :

Given that,

• balloon is moving vertically upwards with a velocity of 4 m/s
• a stone is dropped from it when balloon is at a height of h
• stone reaches the ground in 4 seconds

we need to find,

• Height of balloon when stone is released

so,

Let us assume the upwards motion as negative and downward motion as positive ,

then,

• initial velocity of stone, u = - 4 m/s

[ since stone is moving upwards with the balloon initially ]

• time taken by stone to cover a distance h , t = 4 sec
• acceleration due to gravity, g = +9.8 m/s²

[ since, stone is thrown in downward direction ]

Using second equation of motion

→ s = u t + 1/2  a t²

[ where s is distance covered, u is initial velocity, t is time taken, and a is acceleration ]

→ h = u t + 1/2 g t²

→ h = (-4) (4) + 1/2 (9.8) (4)²

→ h = -16 + 4.9 (16)

→ h = 62.4 m

therefore,

• Height of balloon when stone is released is 62.4 metres .