A constant power delivering machine has towed a box, which was initially at rest, along a horizontal straight line. The distance moved by the box in time $t$ is proportional to:-\\
(1) $t ^ { \frac { 2 } { 3 } }$\\
(2) $t ^ { \frac { 3 } { 2 } }$\\
(3) $t$\\
(4) $t ^ { \frac { 1 } { 2 } }$