Ten questions. The result tells you which lessons you may skip.
A rope pulls a box with a force of \(20\,\text{N}\) at \(60°\) above the horizontal. The box moves \(5\,\text{m}\) along the level floor. The work done by the rope is
A ball is thrown straight up. While it rises, the work done on it by gravity is
A force rises steadily from \(0\) to \(10\,\text{N}\) over the first \(2\,\text{m}\) of a displacement, then stays at \(10\,\text{N}\) for \(1\,\text{m}\) more. The work done by the force is
A spring with \(k = 400\,\text{N/m}\) is stretched slowly from its natural length by \(5\,\text{cm}\). The work done by the hand is
A \(1\,\text{kg}\) stone is carried along a winding path from a height of \(5\,\text{m}\) down to a height of \(2\,\text{m}\) (\(g = 10\,\text{m/s}^2\)). The work done by gravity is
A crate rides without slipping on the flat bed of a truck that is speeding up. The work done on the crate by friction is
Two skaters at rest on smooth ice push each other apart. The total work done by the two pushing forces is
A \(2\,\text{kg}\) body speeds up from \(2\,\text{m/s}\) to \(4\,\text{m/s}\). The net work done on it is
A car brakes with the same force from three times its usual speed. Its stopping distance becomes
A car moves at a steady \(20\,\text{m/s}\) on a level road against a resistance of \(500\,\text{N}\). The power of its engine is