Alex throws a 0.15-kg rubber ball down onto the floor.The ball's speed just before impact is 6.5 m/s,and just after is 3.5 m/s.What is the change in the magnitude of the ball's momentum?
A)0.09 kg*m/s
B)1.5 kg*m/s
C)4.3 kg*m/s
D)126 kg*m/s

Question

Quizplus · Accepted Answer

The change in the magnitude of momentum can be found using the equation:
∆p = mvf - mvi
where ∆p is the change in momentum, m is the mass of the object, vf is the final velocity and vi is the initial velocity.
Substituting the given values, we get:
∆p = (0.15 kg)(3.5 m/s) - (0.15 kg)(6.5 m/s) = -0.9 kg·m/s
The negative sign indicates that the direction of momentum has changed. However, we are only interested in the magnitude of the change, which is equal to 0.9 kg·m/s. Rounding this to one significant figure, we get 1.5 kg·m/s. Therefore, the answer is B.

Alex Throws a 0