A student moves a box of books down the hall

Question

by pulling on a rope attached to the box. The
student pulls with a force of 179 N at an angle
of 29.8
◦
above the horizontal. The box has a
mass of 42.2 kg, and µk between the box and
the floor is 0.2.
The acceleration of gravity is 9.81 m/s
2
.
Find the acceleration of the box.
Answer in units of m/s
2

Answer 1

remember that fricion is dependent on Normal force. But the vertical component of pulling is upward, so it lessens weight.

Net force=mass*a
horizonalpulling-friction=ma
solve for a.