A 3.0 kg crate is pulled along a rough horizontal surface by a constant 10 N force…
PHYSICS · Single correct · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
A 3.0 kg crate is pulled along a rough horizontal surface by a constant 10 N force that is directed 30° above the horizontal. Before the force was redirected upward, the same 10 N force applied horizontally kept an identical crate moving at constant velocity on the same surface. Which statement best describes the crate’s horizontal acceleration immediately after the force is redirected upward?
(a) It is zero because the horizontal component of the applied force is unchanged.
(b) It is negative because the horizontal component of the applied force (10cos30∘) is now less than the kinetic-friction force of 10N.
(c) It is greater than zero because the reduced normal force lowers the kinetic-friction force.
(d) It is zero because the coefficient of kinetic friction is unchanged, so the kinetic-friction force is still 10N.