Solve the given problems.
A force P (in lb) at an angle θ above the horizontal drags a 50-lb box across a level floor. The coefficient of friction between the floor and the box is constant and equals 0.20. The magnitude of the force P is given by
![1455_5990fea7-2600-4338-a94c-fd5bc5d7c5a8.png](https://secure.tutorsglobe.com/CMSImages/1455_5990fea7-2600-4338-a94c-fd5bc5d7c5a8.png)
Find θ such that P is a minimum.