Two billiard balls of mass 0.05 kg each moving in opposite directions with 10 ms^$$-$$1 collide and rebound with the same speed. If the time duration of contact is t = 0.005 s, then what is the force exerted on the ball due to each other?

For a free body diagram shown in the figure, the four forces are applied in the 'x' and 'y' directions. What additional force must be applied and at what angle with positive x-axis so that the net acceleration of body is zero?

Capacitance of an isolated conducting sphere of radius R₁ becomes n times when it is enclosed by a concentric conducting sphere of radius R₂ connected to earth. The ratio of their radii $$\left( {{{{R_2}} \over {{R_1}}}} \right)$$ is :

The ratio of wavelengths of proton and deuteron accelerated by potential V_p and V_d is 1 : $$\sqrt2$$. Then the ratio of V_p to V_d will be :