Question

A ball is dropped from a balloon going up at a speed of 7m/s if the balloon was at a height 60m at the time of dropping the ball how long will the ball taken in reaching the ground

Answer 1

hey ball's displacement=-60m

so -60=7t-1/2×10×t^2

-60=7t-5t^2

5t^2-7t-60=0


comparing with ax^2+bx +c=0

a=5 b=-7 c=-60


t=(-b+-√b^2-4ac)÷2a

=(7+-√49+1249)÷10

=42.34/10
=4.234 sec