A robot is used to move boxes in a factory. A box is pulled up a slope inclined at $30^{\circ}$ to the horizontal by a rope connected to the robot. The tension $T$ .
Ⅰ.Define work done by a force.
Ⅱ.The box is moving at a constant speed. It covers $1.2\,m$ in $3\,s$.
1.The output power of robot $W$
2.During the pull, the robot has a potential difference of $24\,V$ across the terminals of its battery and a current of $3.0\,A$ derived from the battery. Determine the efficiency of the robot in this situation. %
3.The emf of the battery is $32\,V$. Calculate the internal resistance of the battery. $\Omega$
Ⅲ.The rope connecting the robot and the box breaks at a height of $1.5\,m$ from the ground level
1.The maximum height above the ground level reached by the box is $1.505\,m$ . Show that the work done by friction on the box after the break up to reach the maximum height is $J$.
2.The coefficient of dynamic friction between the box and the incline .
3.The box experiences friction both on the way up the slope and also as it slides back down the slope. On the graph below, sketch the variation of the speed $v$ of the box with the time $t$ passed from when the rope breaks until the box reaches the ground level.
