Answer to Question #265001 in Mechanics | Relativity for jung2

Question

In a cheerdancing competition, a 65.0 kg cheerleader is tossed vertically upward

with a speed of 3.75 m/s. a) what is the initial momentum of the cheerleader at

the moment she was tossed up? b) what is her momentum just before being

caught, assuming she was caught at the same height? c) what is the change in

momentum of the cheerleader?

Answer 1

a) The momentum is

$$p_i=mv=243.8\text{ kg}·\text{m/s up}.$$

b) The momentum is the same but in the opposite direction:

$$p_f=mv=243.8\text{ kg}·\text{m/s down}.$$

c) The change in momentum is

$$\Delta p=p_f-p_i=243.8\text{ up}-(-243.8\text{ up})=487.6\text{ kg}·\text{m/s}.$$