Question

A ball is launched upwards from a height of 4 feet. The ball’s height as a function of time, in seconds, is modeled by the function h(t)= -16t^2 +80t +4. What is the time interval in which the ball has a height greater than 100 feet?

Answer 1

Between 2 & 3 seconds. Or we can write it as 2<t<3

Explanation:

t = elapsed time in seconds

h(t) = height of the ball at time t

So we just need to replace h(t) with 100 and start to solve. In the end, the answer will be t=2, or t=3 or we can write it as 2<t<3. You can check it by plugging in the number into the equation.