Question

A force F at an angle θ above the horizontal is used to pull a heavy suitcase of weight mg a distance d along a level floor at constant velocity. The coefficient of friction between the floor and the suitcase is µ. The work done by the frictional force is:a. – µFdcosθb. –Fdcosθc. –µmgdd. –µmgdcosθ

Answer 1

Answer:

option B

Explanation:

given,

Force = F

angle of inclination, = θ

distance = d

coefficient of friction = μ

work done =frictional Force x displacement

W = f. s

friction force on the incline will be equal to horizontal of force component. so,

f = - F cos θ

Work done will be equal to

W = - F d cos θ

Hence, the correct answer is option B