Solve Flight Attendant's Work Problem: A, B & C

[feddyfuntime]

[Mentor note: Misplaced homework thread moved from technical forum, hence no template shown]

A flight attendant pulls her 70N flight bag a distance of 253 meters along a level airport floor at a constant velocity. The force she exerts is 40 Newtons at an angle of 52 degrees above the horizontal, find the following:
a. the work she does on the flight bag
b. the work done by the force of friction on the flight bag
c. the coefficient of kinetic friction between the flight bag and the floor.

I think I understand A, which is 6230.5J? But B and C I do not even know where to start, please help? Thanks in advanced.

 

[Doc Al]

How might you figure out the friction force? Hint: constant velocity.

 

[Andrew Mason]

A flight attendant pulls her 70N flight bag a distance of 253 meters along a level airport floor at a constant velocity. The force she exerts is 40 Newtons at an angle of 52 degrees above the horizontal, find the following:
a. the work she does on the flight bag
b. the work done by the force of friction on the flight bag
c. the coefficient of kinetic friction between the flight bag and the floor.

I think I understand A, which is 6230.5J? But B and C I do not even know where to start, please help? Thanks in advanced.

Your answer to a. is correct. Since the bag is not accelerating during its passage over the floor, what can you say about the sum of the forces on the bag during that journey? So how is the horizontal component of the pulling force related to the floor's friction force on the bag during that time? From that you should be able to determine the work done by the friction force on the bag over those 253 metres.

For c. you have to state the relationship between kinetic friction force and the normal force and solve for μ_k. What is the normal force? What is the friction force?

AM