Coefficient of Kinetic Energy; What is it and How can I calculate it?by DBAA Tags: coefficient, force, kinetic 

#1
Oct3010, 01:11 PM

P: 2

1. The problem statement, all variables and given/known data
A girl pushes a shovel at uniform velocity across a sidewalk. The handle of the shovel is inclined at 55degrees to the horizontal and the girl pushes the handle with a force of 100N. What is the friction and what is the coefficient of kinetic friction. Given Information from said Question: For both the girl and the shovel a= 0m/s^{2};uniform velocity F_{appx} = 100cos55 F_{appy} = 100sin55 Not Given Information: Mass, therefore gravity nor normal force can be calculated. But we don't need either as far as I know. 2. Relevant equations F_{k}=F_{appx} (in this instance, because F_{netx} is equal to 0 due to acceleration) I don't know an equation for the coefficient of kinetic friction.. 3. The attempt at a solution I solved for force of friction; that was an easy one. F_{k}=100cos55 F_{k}=57.36N[<] (the direction is from my FBD assuming > is positive) I've never heard of "the coefficient of kinetic friction", and we definatly did not learn it in class. A quick use of google didn't give me the exact answer I needed. I then turned to wikipedia (as i love it and it's never let me down), which then told me "The coefficient of friction is an empirical measurement – it has to be measured experimentally, and cannot be found through calculations." Since i don't exist where this question takes place, and don't have her shovel or what it's made of I can't do this experimentally. So if I can't calculate it, and I can't measure it myself, how exactly do i find the coefficient of kinetic energy. What does the coefficient of kinetic energy actually mean? Much thanks ^^ 



#2
Oct3010, 11:11 PM

P: 13

The coefficient of kinetic energy is the constant for which friction is acting as a retarding force to show how much force is actually being applied on the object through the equation F= mu * N where mu is the variable that stands for the coefficient of kinetic energy. there is also a shortcut that can be used when applying force on an angle to find mu which is mu = tan(theta)




#3
Oct3010, 11:21 PM

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#4
Oct3010, 11:34 PM

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Coefficient of Kinetic Energy; What is it and How can I calculate it?
Yes, i do apologize for that confusion. the title says kinetic energy but i did mean kinetic friction.
and is the equation F=(mu)(N) the one I would still use though? I'm not entirely sure what to plug my values in for this. is F the friction that I found (in this question 57.36N<)? If so, what does the N equal? Normal force (that personally doesn't make sense to me because the kinetic friction and normal force are on different axi)? 



#5
Oct3110, 06:42 AM

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