53. ssm mmh Two friends, Al and Jo, have a combined mass of 168 kg. At an ice skating rink they stand close together on skates, at rest and facing each other, with a compressed spring between them. The spring is kept from pushing them apart because they are holding each other. When they release their arms, Al moves off in one direction at a speed of 0.90 m/s, while Jo moves off in the opposite direction at a speed of 1.2 m/s. Assuming that friction is negligible, find Al's mass.

Two balls of mass m and M are attached by strings of length L. The two balls are initially at rest at an angle θ, and are then released. The balls undergo a totally inelastic collision at the bottom of their swings. Assume that m = 1.7kg, M = 2.8kg, L = 0.80m and θ = 67o.a) Calculate the speed of the balls immediately after the totally inelastic collision.b) To what maximum angle do the conjoined balls rise after the collision?

Particle A has mass m and moves directly to the right with speed v > 0. Particle B has four times the mass of Particle A and moves directly to the right with half the speed of Particle A. Which of the following statements are true? (Pick two.) Particle A has greater momentum than Particle B. Particle B has greater momentum than Particle A. Both particles have the same momentum. O Particle A has greater kinetic energy than Particle B. O Particle B has greater kinetic energy than Particle A. Both particles have the same kinetic energy.

A lumberjack is standing on a log floating on a lake. She starts from rest, then runs along the log to the end, when she jumps from the first log onto a second. After landing safely on the second log, she slows down and ends up standing on the second log. Both logs both have masses of 150 kg each and the mass of the lumberjack is 70 kg. The lumberjack reaches a speed of 7.0 m/s relative to the shore during her jump. What is the speed of the lumberjack after she has stopped on the second log? You may assume the drag of the water on the logs is very small. Please answer in units of m/s.