Question

is thrown upwards takes 4 second to reach the maximum height find the initial speed with which it was thrown and the maximum height it reached

Answer 1

•.•at the maximum height final velocity (v)=0
so, by formula v=u-gt (because thrown upward)
.•.0=u-9.8*4
so that initial velocity (u)=39.2m/s answer.
hope this will help you