Question

A stone is thrown upward from the top of a 59.4m high cliff with an upward velocity component of 19.6m/s how long is the stone in the air?
I need it solution

Answer 1

Let downward direction be

-ve

So

S= -59.4m

a=-10ms^-2

u=19.6ms^-1

s=ut+1/2at^2

-59.6=19.6t - 10/2t^2

-59.6 = 19.6t -5t^2

5t^2 - 19.6t - 59.6 =0

Solving this eqn gives the answers 6 and -2

But time is always positive

So answer is 6 seconds