How Is Work Done by Friction Calculated in Physics Problems?

[kiwikahuna]

Homework Statement

A flight attendant pulls her 60.4 flight bag
a distance of 323 m along a level airport floor
at a constant velocity. The force she exerts is
46.0 N at an angle of 61.3° above the horizon-
tal.
a) Find the work she does on the flight bag.
Answer in units of J.
b) Find the work done by the force of friction
on the flight bag. Answer in units of J.
c) Find the coefficient of kinetic friction be-
tween the flight bag and the floor.

Homework Equations

force of friction = normal force X coeffiecent of kinetic friction

The Attempt at a Solution

I have found that the work she does on the flight bag is 7135.16 J and the work done by the force of friction is -7135.16 J.
I can't seem to comprehend how to solve for the coefficient. If you can lend a hand in the right direction, I would appreciate it very much!

 

[Doc Al]

force of friction = normal force X coeffiecent of kinetic friction

That's what you need. Figure out the friction force (you must have figured that one out already) and the normal force.

 

[m2003]

Hello,

I can provide some insights on the concept of work done by friction in this scenario. Friction is a force that opposes the motion of objects in contact with each other. In this case, the flight attendant is exerting a force of 46.0 N on her flight bag at an angle of 61.3° above the horizontal. This force is balanced by the force of friction, which is acting in the opposite direction. Since the flight bag is moving at a constant velocity, the net force acting on it is zero, and therefore the work done by the net force is also zero.

To find the coefficient of kinetic friction, we can use the equation you mentioned, which is force of friction = normal force x coefficient of kinetic friction. In this case, the normal force is equal to the weight of the flight bag, which can be calculated as mass x gravity. We can also use the relationship between work and force, which is work = force x displacement x cosθ, where θ is the angle between the force and displacement. Since the work done by the net force is zero, we can set the work done by the force of friction equal to the work done by the flight attendant, which is 7135.16 J. Solving for the coefficient of kinetic friction, we get a value of 0.117.

I hope this helps in your understanding of work done by friction and how to solve for the coefficient of kinetic friction. Keep up the good work!