A body is moved along a straight line by an engine which delivers a constant power. The distance moved by the body in time $t$ is proportional to

A body of mass 3 kg is moving under the action of a force which causes a displacement of $\left(t^3 / 3\right) \mathrm{m}$, where $t$ is time in seconds. The work done by the force in first 2 sec is

Two blocks of masses 2 kg and 1 kg are tied to the ends of a string which passes over a light frictionless pulley. The blocks are held at the same horizontal level and then released suddenly. The distance traversed by their centre of mass in 2 sec is

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

A particle of mass $m$ is moving along a line $y=x+a$ with a constant velocity $v$. The angular momentum of the particle about the origin is