A 10kg crate rests on a frictionless horizontal floor. Two horizontal ropes pull on the crate: Rope A exerts 40N to the right and Rope B exerts 40N to the left. A scale shows that the normal force equals the crate’s weight. At time t=0, Rope B is suddenly cut. Which of the following best describes the crate’s motion just after t=0?
a) It accelerates diagonally downward because both horizontal and vertical forces become unbalanced.
b) It accelerates to the right at 4m/s2 while its vertical motion remains unchanged.
c) It moves to the right with a constant speed of 4m/s.
d) It remains at rest because the normal force continues to balance its weight.