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posted by  aimster on 10/11/2008 6:12:35 PM  |  status: Live  

Energy/Work Done

Course Textbook Chapter Problem
General Physics Essentials of College Physics 5 3
Question Details:
Starting from rest, a 5.00-kg block slides 2.50m down a rough 30.0o incline.  The coefficient of kinetic friction between the block and the incline is μk = 0.436.  Determine (a) the work done by the force of gravity, (b) the work done by the friction force between block and incline, and (c) the work done by the normal force. 

I am not coming up with the right answers.  So if anyone could help me on this problem it would be greatly appreciated.  (I'm not looking for someone to do the work for me -- just to get pointed in the right direction.)  Thanks in advance! ~Amy
Thanks!!! :D
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posted by Justin_08 on 10/11/2008 8:21:13 PM  |  status: Live
Asker's Rating: Lifesaver   
aimster's comment:
"Thank you! This is exactly what I needed. My picture was off so that messed me up. Anyways thank you again!"
Response Details:
 
 
             Given that the mass of the block si m = 5.00 Kg
             The angle of inclination is θ = 30.00
              The length of the ramp is  L = 2.50 m
               The coefficient of kinetic friction between the block and the incline is μk = 0.436. 
  --------------------------------------------------------------------------------------------------------  
 
                               
 
      The work done due to all the forces is  Wtot = (F+mgsinθ)*L
                                                                          
 (b) The work done by the gravity is 
                               Wg = mg sinθ*L
                                      = ----------- J
 (c)  The work done by the frictional force is 
                               Wf = - (μ mgcosθ)*L 
                                     = ------------- J
  (d) the work done by the normal force is Wn = 0
        ( since there is in displacement in the normal force direction )
 
   
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