SOLUTION: A ball falls from the top of a roof 320 feet above the ground. The formula h = -16t2 + 16t + 320 described the height of the ball above the ground, h, in feet, t seconds after the

Question 345461: A ball falls from the top of a roof 320 feet above the ground. The formula h = -16t2 + 16t + 320 described the height of the ball above the ground, h, in feet, t seconds after the fall begins. How long will it take the ball to strike the ground?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
When the ball hits the ground, , so

Divide both sies by

Use quadratic equation to find

Take the negative square root in order
to get a positive answer:

sec
The ball will hit the ground in 5 sec
check answer:

OK
RELATED QUESTIONS
Use a quadratic equation and factoring to solve the application. A ball falls from the (answered by scott8148)

A ball falls off the top of a roof 320 feet above the ground. The formula h= -16t^2 +... (answered by Greenfinch)

I need help with this problem. A ball is thrown from the top of a roof 320 feet above... (answered by scott8148)

I have asked this ? earlier with no response. A ball is thrown from the top of a roof... (answered by nerdybill)

A girl stands on the edge of her dorm roof and throws a ball into the air. The ball's... (answered by rothauserc)

h=-16t^2-32t+320 gives the height of a ball thrown downward from the top of a 320 foot... (answered by Alan3354)

Using physics, it can be shown that if a ball is thrown upwards with an initial velocity (answered by Alan3354)

The equation h=-16t^2-32t+320 gives the height od a ball, thrown downward from the top of (answered by Nate)

A rocks falls from a tower that is 320 ft high. As it is falling, it height is given by... (answered by jim_thompson5910)