試題詳解

2. A 32-N force, parallel to the incline, is required to push a certain crate at constant velocity up a frictionless incline that is 30° above the horizontal. The mass of the crate is:
(A) 3.3 kg
(B) 3.8 kg
(C) 5.7 kg
(D) 6.5 kg
(E) 16 kg.