Two football players are running toward each other. one football player has a mass of 105 kg and is running at 8.6 m/s. the other player has a mass of 90 kg and is running at –9.0 m/s.
the momentum of the system after the football players collide is kg • m/s.

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?

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.

Part of a control linkage for an airplane consists of a rigid member cb and a flexible cable ab. if a force is applied to the end b of the member and causes it to rotate by θ = 0.5°, determine the normal strain in the cable. originally the cable is unstretched.