Use the exact values you enter in previous answer(s) to make later calculations.

Question

Use the exact values you enter in previous answer(s) to make later calculations.

A rubber ball (mass 0.27 kg) is dropped from a height of 1.8 m onto the floor. Just after bouncing from the floor, the ball has a speed of 4.0 m/s.
(a) What are the magnitude and direction of the impulse imparted by the floor to the ball?
magnitude ...... kg · m/s
direction

(b) If the average force of the floor on the ball is 18 N, how long is the ball in contact with the floor? Ignore the force of gravity during the collision of the ball with the floor.
........ s

Explanation / Answer

Part A)

First we need to find the velocity is had just before striking the floor

vf2 = vo2 + 2ad

vf2 = (0) + (2)(9.8)(1.8)

Vf = 5.94 m/s

The change in momentum is the mass times the velocity change. The velocity change is 9.94 m/s

It went from a downward 5.94 m/s to an upward 4 m/s   (4 - (-5.94)) = 9.94

The impulse momentum therorm is Impulse = p = (mv)

Impulse = (.27)(9.94) = 2.68 Ns and the direction is upward

Part B)

Impulse = Ft

2.68 = (18)(t)

t = .149 sec or 149 ms

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.