A body is projected vertically upwards with a velocity of $20 \mathrm{~ms}^{-1}$. If the potential energy of the body at a height of 5 m from the ground is 100 J , then the kinetic energy of the body at a height of 10 m from the ground is

(Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

If a constant force of $(2 \hat{\mathbf{i}}+3 \hat{\mathbf{j}}+4 \hat{\mathbf{k}}) \mathrm{N}$ acting on a body of mass 5 kg displaces it from $(3 \hat{\mathbf{i}}-4 \hat{\mathbf{k}}) \mathrm{m}$ to $(2 \hat{\mathbf{i}}+2 \hat{\mathbf{j}}+3 \hat{\mathbf{k}})$ m , then the work done by the force on the body is

A motor can pump 7560 kg of water per hour from a well of depth 100 m . If the efficiency of the pump is $70 \%$, then power of the pump is

(Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

If the potential energy of a particle of mass 0.1 kg moving along $X$-axis is $5 x(x-4) \mathrm{J}$, then the speed of the particle is maximum at a position of