Question

A box of mass 10 kg is pulled by a mass-less rope with a force of 40 N. The rope

makes an angle of 30 with the horizontal. Draw the free-body diagram showing

all forces on the box. Determine the acceleration of the box if the coefficient of

kinetic friction between the floor and the box is 0.2. Take   2 g 10 ms .

Answer 1

$$ma=F\cos{30}-\mu N\\N=mg-F\sin{30}\\ma=F\cos{30}-\mu (mg-F\sin{30})\\ 10a=40\cos{30}-0.2 (10(9.8)-40\sin{30})\\a=1.9\frac{m}{s^2}$$