Calculate the power spent by a crane while lifting a load of mass 2000 kg, at velocity of 1.5 ms^-1. (g = 10 ms^-2).

(a) Which electrical component protects the electric circuit in case of excess current and which can also be used as a switch?

(b) Name the wire to which this electrical component is connected in an electric circuit.

(a) Is it possible for a concave lens to form an image of size two times that of the object? Write Yes or No.

(b) What will happen to the focal length of the lens if a part of the lens is covered with an opaque paper?

A metal foot ruler is held at the edge of a table. It is pressed at its free end and then released. It vibrates.

(a) Name the vibrations produced.

(b) State one way to increase the frequency of these vibrations.