Beckles

A net force of 47.0 N acts on a 53.0 kg body initially at rest. Compute the work (in joules) done by the force in the first second of time. Not sure where to start at all :(

What power (in horsepower) is developed by a grinding machine whose wheel has a radius of 8.10 in and runs at 2.50 rev/s, when the tool to be sharpened is held against the wheel with a force of 43.0 lb? The coefficient of friction between the tool and the...