Box being Pulled - acceleration?

Question

A 70kg box is pulled by a 400N force at an angle of 30 degrees to the horizontal. The force of kinetic friction is 75 N.

What is the acceleration of the box?

Answer 1

Its kind of a strange problem because they are giving you a frictional force instead of a coefficient of friction.

First resolve the forces in to vertical (y) and horizontal (x) components.

400 N at 30 degrees

Forces in vertical are 400 x sin (30)

Forces in Horizontal are 400 x cos (30) - 75

F = ma so, a = F/m a,x = 400sin(30)/ 70

a,y = (400 cos(30) - 75)/70