A box of mass $10\ \text{kg}$ rests on a rough horizontal floor. The coefficient of friction between the box and the floor is $0.75$. You pull the box with a rope that makes an angle $\theta$ above the horizontal, as shown in the figure. Taking $g = 10\ \text{m/s}^2$, the smallest pull that can just start the box moving, and the angle at which it acts, are

Fig. 1: A 10 kg box on a rough floor, pulled by a rope at an angle theta above the horizontal with a force F. The floor has a coefficient of friction of 0.75.