General questions: A box of mass m is pulled with a constant acceleration a along a horizontal frictionless floor by a wire that makes an angle of 15° above the horizontal. If T is the tension in this wire, then A) T = ma. B) T ma. C) T

Question

General questions: A box of mass m is pulled with a constant acceleration a along a horizontal frictionless floor by a wire that makes an angle of 15° above the horizontal. If T is the tension in this wire, then
A) T = ma.
B) T > ma.
C) T < ma.

Quizplus · Accepted Answer

The tension in the wire must be greater than the mass times the acceleration since it also has to counteract the component of gravity that is parallel to the floor. This component has a magnitude of mgsin(15°), where g is the acceleration due to gravity. Therefore, the total force on the box is T - mgsin(15°) = ma. Rearranging, we get T = ma + mgsin(15°). Since sin(15°) is a positive number, T must be greater than ma.

General Questions: a Box of Mass M Is Pulled with a Constant