Question

It would be appreciated if all questions were answered and have shown work. :)

1. While skiing, Sam flies down a hill and hits a jump. He has a mass of 75 kg, and he leaves the jump at 18 m/s. What is his momentum as he leaves the jump?


2. How fast would a 0.25 kg football have to be traveling to have the same momentum as a 0.05 kg bullet travelling 500 m/s?


3. Sarah, who has a mass of 55 kg, is riding in a car at 20 m/s. She sees a cat crossing the street and slams on the brakes! Her seat-belt stops her from flying forward, bringing her to rest in 0.5 seconds. How much force did the seat-belt put on Sarah?

Answer 1

1)

P = mv

P=75 (18) = 1350 kg-m/s

2)

0.25 v= 0.05 (500)

V= 100 m/s

3)

∆ mv = F∆t

55(20) =F(0.5)

Answer 2

1. The formula for momentum is:
p = mv
p =75(18) = 1350 kg-m/s

2. We equate the momentum of the two objects
0.25 v = 0.05 (500)
v = 100 m/s

3. We use the formula for impulse:
Δmv = FΔt
55(20) = F(0.5)
F = 2200 N