Question

A ball is thrown vertically upward from ground level with an initial velocity of 80 feet per second. The ball's h height after t seconds is given by the equation h = −16t2 + 80t. How long will it take for the ball to hit the ground?

Answer 1

A

Explanation:

It only takes 5 seconds friend.

Answer 2

The ball will take 5 seconds to hit the ground.

Explanation:

The ball's h height after t seconds is given by the equation h = −16t² + 80t

When the ball hit the ground, the height will be zero.

∴ h = −16t² + 80t = 0

∴ −16t² + 80t = 0 take t as common

t ( -16t + 80) = 0

∴ t = 0 Or -16t + 80 = 0

-16t + 80 = 0

-16t = -80

t = -80/-16 = 5 seconds

So, The ball will take 5 seconds to hit the ground.