Question

A ball is thrown directly upward from a height of 7 feet with an initial velocity of 50 ft./s use the quadratic formula to find the number of seconds it takes the ball to hit the ground

Answer 1

The time taken by ball to hit the ground is 5.10 seconds .

Explanation:

Given as :

The height cover by ball to move upward = 7 feet

The initial velocity = u = 50 feet per sec

Let the time taken by ball to hit the ground = t sec

Let the deacceleration rate = - 9.8 m/s²

The final velocity of the ball = v= 0 at the top

So, From equation

v = u + at

I.e v = u + a × t

Or, 0 = 50 + ( - 9.8) × t

Or, 9.8 t = 50

∴ t =
`(50)/(9.8)`

I.e t = 5.10 seconds

So, time taken = 5.10 sec

Hence The time taken by ball to hit the ground is 5.10 seconds . Answer