Questions 14-15
A block of mass m is accelerated across a rough surface by a force of magnitude F that is exerted at an angle ϕ with the horizontal, as shown above. The frictional force on the block exerted by the surface has magnitude f.
14. What is the acceleration of the block?
(A) F/m
(B) (Fcosϕ)/m
(C) (F-f)/m
(D) (Fcosϕ−f)/m
(E) (Fsinϕ−mg)/m