What is the momentum of a child and her "skiing penguin" whose combined mass is 45 kg that slides at 5 m/s across the ice? b). The child and her toy hit a rough surface that stops them in 3 s. Calculate the force of friction that they encounter. Sketches required.

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.