Question

A balloon is going vertically upwards with s velocity of 10m/s. When it is 75m
above the ground, a stone is gently released from it. The time taken by the stone
to reach the ground is (8 = 10 m/s)
1) 3s
2) 4s
3) 5s
4) 6s​

Answer 1

EXPLANATION:

★WE HAVE,,

Consider upward motion +ve and downward motion -ve.

•Velocity of balloon=initial velocity of stone,u=+10m/s

•Distance to be travelled by the stone,s=-75m

•Acceleration due to gravity,a=-g=-10m/s

________________________________

By using 2nd equation of motion, we get,,

s=ut-½gt²

→-75=10t-½×10t²

→-75=10t-5t²

→5t²-10t-75=0

→t²-2t-15=0

→t²-5t+3t-15=0

→(t-5)(t+3)=0

→t=5 or t=-3

Taking t +ve (since it can't be -ve),,we get,,

Time taken by the stone to reach the ground,,t=5s

Thus 3rd option is the correct answer...

________________________________

HOPE IT HELPS ❣️❣️❣️

________________________________