Question

9. A 0.180-kg ball is dropped from rest. If the magnitude of the ball's momentum is 0.780 kg · m/s just before it lands on the ground, from what height was it dropped?

Answer 1

Mass m = 0.18 kg

Initial speed u = 0

the magnitude of the ball's momentum just before it lands on the ground P = 0.780 kg · m/s

We know P = mv

From this velocity just before hit the ground v = P / m

       v = 0.78 / 0.18

         = 4.333 m/s

Let the height was it dropped be h

We know v = [2gh]

from this h = v ²/ 2g

                 = 4.33 ² /(2x9.8)

                = 0.958 m