A speedboat accelerates uniformly. At t = 30.0 s, it is traveling 10.0 m/s; at t= 50.0 s it is traveling 20.0 n What is the acceleration of the speedboat?

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.