Question

An astronaut on the moon throws a ball vertically upwards. The height, s metres, of the ball, after t seconds, is given by the equation s= 40t + 0.5at^2, where a is a constant. If the ball reaches its maximum height when t = 25, find the value of a.

Answer 1

a=-1.6
differenciate wrt t
ds/dt = 40+ at
to maximise s, make the ds/dt zero..
so, a=-40/t=-40/25=-1.6

Answer 2

a will be -1.6

Answer 3

THANK YOU!! :D

Answer 4

could someone explain the process of solving that problem?