You are standing on a sheet of ice that covers the football

You are standing on a sheet of ice that covers the football stadium parking lot in Buffalo; there is negligible friction between your feet and the ice. A friend throws you a 0.200-kg ball that is traveling horizontally at 10.0 m/s. Your mass is 79.0 kg .

Part A

If you catch the ball, with what speed do you and the ball move afterward?

Express your answer with the appropriate units.

v =

Part B

If the ball hits you and bounces off your chest, so afterward it is moving horizontally at 8.0 m/s in the opposite direction, what is your speed after the collision?

Express your answer with the appropriate units.

v =

Solution

Apply conservation of momentum to the system of you and the ball.

Let x be in the direction the ball is traveling initially

m_A = 0.200 kg , m_B = 79.0 kg

a) P_1x = P_2x

(0.200 * 10) = (0.200 + 79) v₂

v₂ = 0.025 m/s

b) P_1x = P_2x

(0.200 * 10) = (0.200 * -8.0) + ( 79 * v_B)

v_B = 0.0455 m/s