# Al and Jo?

Two friends, Al and Jo, have a combined mass of 163 kg. At the ice skating rink, they stand close together on skates, at rest and facing each other. Using their arms, they push on each other for 1 second and move off in opposite directions. Al moves off with a speed of 10.4 m/sec in one direction and Jo moves off with a speed of 11.9 m/sec in the other. You can assume friction is negligible.

I found that Al's mass is 86.982 and Jo's mass is 76.018.

1. If you assume the force is constant during the 1 second they are pushing on each other, what is the magnitude of the force of Al on Jo?

2. If you assume the force is constant during the 1 second they are pushing on each other, what is the magnitude of the force of Jo on Al?

Relevance

An impulse will result in a change in momentum

FΔt = mΔv

F = mΔv/Δt

1) Force of Al on Jo

F = 76.0(11.9 - 0) / 1.00

F = 904 N

1) Force of Jo on Al

F = 87.0(10.4 - 0) / 1.00

F = 904 N

Not so amazingly, these two forces are identical. Showing that for every action, there is an equal and opposite reaction.

I hope this helps.

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