Question

The height of a ball thrown directly up with a velocity of 10 feet per second from a initial height of of 100 feet is given by the equation , 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

2.8 seconds

Explanation:

Given that a ball is thrown directly up

Initial velocity u = 10 ft/sec INitial height = 100 ft

t = time from time of throw

The equation as

`h(t) =-16t^2+10t+100`

Since h(0) =100 we find that h is measured from earth

When the ball hits the ground h=0

So we have

`h(t)=0 =-16t^2+10t+100`

Use binomial formulae to solve this to get

t=2.832 or t =-2.207

Since time cannot be negative

we get t=2.832

At 2.8 seconds ball hits the ground