THIS IS DUE IN A FEW HOURS PLEASE HELP!! A crane lifts a 614 kg roof 9.3 m high above the ground at a constant speed. It takes 48.4 seconds to do so.
Calculate the work done by the crane.

If the wheels lock when braking suddenly the vehicle: a: loses traction b: lose steering wheel ability c: gain speed slightly d: gain steering ability

What is a good example of instantaneous speed

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.