Question

The height of a ball thrown directly up with a velocity of 40 feet per second from a initial height of of 5 feet is given by the equation h(t)=-16t^2+40t+5, where t is the time in seconds and h is the ball’s height, measured in feet. When will the ball hit the ground? Round your answer to the nearest tenth.

Answer 1

When it hits the ground , h(t) = 0 , so

-16t^2 + 40t + 5 = 0
16t^2 - 50t - 5 = 0

Now solve this quadratic using the method that you learned.
One of the answers will be negative, you would reject that one.

Answer 2

12

Answer 3

2.5