Physics Past Questions and Answers

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.

A rope is being used to pull a mass of 10kg vertically upward. Determine the tension in the rope if, starting from rest, the mass acquires a velocity of 4ms\(^{-1}\) in 8s [g = 10ms\(^{-2}\)]

I. The frictional force is independent of the area of the surfaces in conduct
II. The frictional force depends on the nature of the surfaces in contact
III. The frictional force depends on the speed of sliding
IV. The frictional force is directly proportional to the normal reaction.
Which combination of the above is true of sliding friction?