Question

A body is dropped from a balloon which is moving upward with a speed of 10m/s.The body is dropped when the balloon is at a height of 390m from the surface of earth.Find the approximate time taken by the body to reach the surface of earth.Take g=10m/s2.​

Answer 1

Explanation:

First, we write all the known quantities

a=-10m's^2.

s=390m

u=+10m/s

s=ut+1/2at^2

s 10t+5t^2

-390=10t+5t^2.

-78=2t=78=0

d=b^2-4ac.

d=4+312.

d=316.

-b+-root d/2a.

2+-2root 79/2=1+-79.

therefore time taken to hit the ground will be 1+79.

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