Question

A ball is thrown upward with an initial velocity of 10 meters per second. If the ball's height is given by s = -4.9t^2 + 10t + 1.5 meters after t seconds, find t when the maximum height is reached.

Answer 1

your equation is a parabola, with the vertex at its top.
Can you find the "x value" (here x is t) of the vertex using -b/(2a) ?

Answer 2

Okay, got it. Thanks! @phi

Answer 3

you should get t=10/9.8= 1.02 seconds (very close to 1 second)