Question

Marta throws a baseball with an initial upward velocity of 60 feet per second. Ignoring Marta's height, how long after she releases the ball will it hit the ground?

Answer 1

Answer:

Time, t = 3.75 seconds

Step-by-step explanation:

Given that,

The initial speed of the baseball, u = 60 ft/s

We need to find the how long after she releases the ball will it hit the ground.

The height of an object as a function of time is given by the following equation as :

$h(t)=-16t^2+ut+h_o$

Here h(t) is height in feet

t is in seconds

$h_o$ is initial height

In this case, the height as a function of time is given by :

$h(t)=-16t^2+60t$

When the ball hits the ground, h(t) = 0

$-16t^2+60t=0\\\\t(-16t+60)=0\\\\t=3.75\ s$

So, the ball will hit the ground at 3.75 seconds. Hence, this is the required solution.

Answer 2

Answer:

Step-by-step explanation:

initial velocity, u = 60 feet / second

Let the time taken by the ball to reach the maximum height is t.

at maximum height the final velocity is zero. g = 32 feet/s².

Use first equation of motion

v = u + at

0 = 60 - 32 x t

t = 1.875 s

Time taken by the ball to come to ground, T = 2 x t = 2 x 1.875 = 3.75 s