Okay I have :

a ball is thrown with an initial velocity of 40 ft/second from a height of 4 feet. h(t)=-16t+40t+4

a) what is the highest point reached by the ball?

b) at what time will the ball reach the highest point?

2 answers

your formula is wrong.
h(t)=-16t^2 + 40t+4

v(t)=40-16t
so max height is when v(t)=0 or t=40/16
and the max height is found by plugging that into the height equation.
5 seconds