Question

Help with this question ASAP!

Answer 1

After 4s

Explanation:

Given the ball is initially projected upwards with a velocity of 64ft per sec and we are required to find the time at which it reaches the ground .There are many approaches to solve this problem we will follow this one:

It is also known as the time of flight for the ball which can be found by doubling the time taken for the ball to reach to its maximum height or the point where velocity is zero.

Now
`h(t)=-16* t^(2) +v_(0) * t+h_(0)`

For the time taken to reach the max height
`(dh)/(dt) =0`.

Which implies that -32t+v=0.

∴Time taken to travel halfway through the path =2sec.

∴total time =
`2* 2=4sec`