A box $M_1$ of mass 5 kg and a weight $M_2$ of mass 8 kg are joined by a light inextensible string. The string passes over a small smooth pulley at the top of a rough ramp. The ramp is inclined at an angle $\varphi$ to the horizontal where $\tan \varphi =0.75$. The coefficient of friction between the box and the ramp is 0.3. $M_1$ is placed on the ramp and $M_2$ is suspended 3 m above the floor. The system is released from rest with the string taut. Assume $M_2$ hits the floor before $M_1$ reaches the pulley.