The power of a gun which fires 120 bullet per minute with a velocity $$120 \mathrm{~ms}^{-1}$$ is : (given the mass of each bullet is $$100 \mathrm{~g}$$)

A particle is projected at an angle $$30^{\circ}$$ with horizontal having kinetic energy $$K$$. The kinetic energy of the particle at highest point is.

A long spring, when stretched by a distance $$x$$, has potential energy $$U$$. On increasing the stretching to $$n x$$, the potential energy of the spring will be

If reaction is $$\mathrm{R}$$ and coefficient of friction is $$\mu$$, what is work done against friction in moving a body by distance $$\mathrm{d}$$ ?