Physics Past Questions and Answers

The velocity ratio of a machine is 5 and its efficiency is 75%. What effort would be needed to lift a load of 150N with the machine?

At a fixed point below a liquid surface, the pressure downwards is P1 and pressure upwards is P2. It can be deduced that

If the force and the velocity on a system are each reduced simultaneously by half, the power of the system is

A catapult used to hold a stone of mass 500g is extended by 20cm with an applied force F. If the stone leaves with a velocity of 40m/s, the value of F is

A stream is flowing at 0.75ms\(^{-1}\) and a boat heading perpendicular for the stream landed at the opposite bank at an angle of 30°. Calculate the velocity of the boat.