2. When the spring of a watch is wound, it will possess
A : strain energy
B : kinetic energy
C : heat energy
D : electrical energy
3. The angle of inclination with the vertical is __________ if the cyclist is running at a faster speed than that when he is running at a slower speed.
4. An irregular body may have more than one centre of gravity.
6. In a screw jack, the effort required to lift the load is given by(where W = Load lifted, ? = Helix angle, and ? = Angle of friction.)
A : P = W tan (? - ?)
B : P = W tan (? + ?)
C : P = W tan (? - ?)
D : P = W cos (? + ?)