Question

A balloon starting from the ground has been
ascending vertically at a uniform velocity for 4.5
sec and a stone let fall from it reaches the ground
in 7 sec after release. Find the velocity of the
balloon and its height when the stone was let
fall.
​

Answer 1

Dear Students,

● Answer -

v = 54.44 m/s

s = 245 m

◆ Explanation -

Stone reached the ground in 7 s.

s = ut + ½at²

s = (v-at)t + ½at²

s = (0-10×7)7 + ½ × 10 × 7²

s = -490 + 245

s = 245 m

Velocity of ballon is calculated by -

v = s / t

v = 245 / 4.5

v = 54.44 m/s

Therefore, velocity of the balloon is 54.44 m/s and it's at 245 m from ground when stone is thrown.

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