Dana uses a rope to pull a box that weighs 300 N across a level surface with constant velocity.The rope makes an angle of 25° above the horizontal and the tension in the rope is 100 N.What is the coefficient of friction?
A) 0.35
B) 0.20
C) 0.50
D) 2.14
E) 0.47

Question

Dana uses a rope to pull a box that weighs 300 N across a level surface with constant velocity.The rope makes an angle of 25° above the horizontal and the tension in the rope is 100 N.What is the coefficient of friction?
A) 0.35
B) 0.20
C) 0.50
D) 2.14
E) ​0.47

Quizplus · Accepted Answer

The horizontal component of the tension is 100 N * cos(25°). The frictional force equals this horizontal component since the box moves with constant velocity. The normal force is the weight minus the vertical component of the tension (100 N * sin(25°)). The coefficient of friction is the frictional force divided by the normal force, which calculates to approximately 0.35.

Dana Uses a Rope to Pull a Box That Weighs