On an ice skating rink, a girl of mass 50 kg stands stationary, face to face with a boy of mass 80 kg. The children push off of one another, and the boy moves away with a velocity of +3 m/s. What is the final velocity of the girl?

–1.9 m/s
+1.9 m/s
–4.8 m/s
+4.8 m/s

Arowboat passenger uses an oar to push the boat off the dock by exerting a force of 40n for 3.0s. what impulse acts on the boat.

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.

Auniform crate c with mass mc is being transported to the left by a forklift with a constant speed v1. what is the magnitude of the angular momentum of the crate about point a, that is, the point of contact between the front tire of the forklift and the ground