Question

PLEASE HELP!!! 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 seatbelt stops her from flying forward, bringing her to rest in 0.5 seconds. How much force did the seatbelt put on Sarah?

4. A big league hitter attacks a fastball! The ball has a mass of 0.16 kg. It is pitched at 38 m/s. After the player hits the ball, it is now traveling 44 m/s in the opposite direction. The impact lasted 0.002 seconds. How big of a force did the ballplayer put on that ball?

Answer 1

#1

mass of Sam = 75 kg

velocity of Sam = 18 m/s

now for momentum we can use

$P = mv$

$P = 75(18)$

$P = 1350 kg m/s$

#2

Momentum of football = momentum of bullet

$P_{ball} = P_{bullet}$

$m_{ball}v_{ball} = m_{bullet}v_{bullet}$

$0.25 v = 0.05 (500)$

$v = 100 m/s$

#3

As per Newton's law we know that net force is given as

$F = \frac{\Delta P}{\Delta t}$

now we have

$\Delta P = m(v_f - v_i)$

$\Delta P = 55(20 - 0) = 1100 kg m/s$

also we know that

$\Delta t = 0.5 s$

form above equation we have

$F = \frac{1100}{0.5} = 2200 N$

#4

As per Newton's law we know that net force is given as

$F = \frac{\Delta P}{\Delta t}$

now we have

$\Delta P = m(v_f - v_i)$

$\Delta P = 0.16(44 - (-38)) = 13.12 kg m/s$

also we know that

$\Delta t = 0.002 s$

form above equation we have

$F = \frac{13.12}{0.002} = 6560 N$

Answer 2

Answer:

the guy above me is correct i took the test

Explanation: