How to find he coefficient of kinetic friction?

[snash1057]

A flight attendant pulls her 70.0 N flight bag a distance of 269 m along a level airport floor at a constant speed. The force she exerts is 32.0 N at an angle of 52.0° above the horizontal.

(a) Find the work she does on the flight bag.
_5299_J

(b) Find the work done by the force of friction on the flight bag.
_-5299_ J
(c) Find the coefficient of kinetic friction between the flight bag and the floor.
____

i found part A, by 32.0 x 269 x cos(52.0) = 5299J

but i don't understand how to get part c

i keep doing 32Cos(52)=70-32sin(52)k and i get .1357, don't get what I am doing wrong HELP!??

 

[256bits]

What is the matter with the value .1357?

 

[snash1057]

the answer is .4397

 

[SammyS]

What is the normal force the floor exerts on the flight bag?

Draw a Free Body Diagram.

 

[asteriatic]

To find the coefficient of kinetic friction, you need to use the equation: F_f = μ_k * N, where F_f is the force of friction, μ_k is the coefficient of kinetic friction, and N is the normal force (equal to the weight of the object in this case, which is 70.0 N).

For part (b), you have already calculated the work done by the force of friction (5299 J), so you can use that value in the equation: W = F_f * d, where W is the work done, F_f is the force of friction, and d is the distance (269 m). This will give you the force of friction, which you can then use in the equation F_f = μ_k * N to solve for μ_k.

So, the steps to find the coefficient of kinetic friction would be:

1. Calculate the work done by the force of friction (5299 J).
2. Use the equation W = F_f * d to solve for F_f.
3. Use the equation F_f = μ_k * N to solve for μ_k.

Hope this helps clarify the process!