A force of 4 kN is used to jack up the rear axle of a car by 25 mm. If this requires the operator of the jack to exert a force of 250 N through a distance of 0.6 m, what is (a) the velocity ratio, (b)...

A force of 4 kN is used to jack up the rear axle of a car by 25 mm. If this requires the operator of the jack to exert a force of 250 N through a distance of 0.6 m, what is (a) the velocity ratio, (b) the mechanical advantage and (c) the effciency of the jack?