Question

You drop a ball from a set of bleachers that is 64 feet above the ground.
How long will it take the ball to hit the ground?
(Use the vertical motion model h = 1672 + Wt+s where height is measured in feet
and time is measured in seconds)

Answer 1

Answer:

  2 seconds

Step-by-step explanation:

Filling in the given values in the appropriate ballistic motion formula, we have ...

  $h(t)=-16t^2+v_0t+s_0\qquad\text{initial vertical velocity v_0 , and initial height s_0 }\\\\h(t)=-16t^2+64\qquad\text{ v_0=0 and s_0=64 }\\\\t^2=4\qquad\text{divide by 16, add t^2 }\\\\t=2\qquad\text{take the positive square root}$

It will take the ball 2 seconds to hit the ground.