A crate rests on a frictionless horizontal floor

PHYSICS · Single correct · AP · Physics C: Mechanics · Force and Translational Dynamics · Force and Translational Dynamics

Problem

10\,\text{kg}

crate rests on a frictionless horizontal floor. Two horizontal ropes pull on the crate: Rope A exerts

40\,\text{N}

to the right and Rope B exerts

40\,\text{N}

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

4\,\text{m/s}^2

while its vertical motion remains unchanged. (c) It moves to the right with a constant speed of

4\,\text{m/s}

. (d) It remains at rest because the normal force continues to balance its weight.