View Full Version : Power up and incline with friction
Kajayacht
Sep29-08, 04:40 PM
1. The problem statement, all variables and given/known data
A 1400 kg block of granite is pulled up an incline that has an angle of inclination θ = 29 ° with a constant speed of 1.13 m/s by a steam winch (see Figure). The coefficient of kinetic friction between the block and the incline is 0.12. How much power must be supplied by the winch?
2. Relevant equations
T= uW/cos(theta)+u*sin(theta)
P=Fv
3. The attempt at a solution
T= .12(1400*9.8)/cos(29)+.12*sin(29)
T= 1765.0 N
P= FV
P= 1765*1.13
P= 1994.5 W
LowlyPion
Sep29-08, 04:51 PM
1. The problem statement, all variables and given/known data
A 1400 kg block of granite is pulled up an incline that has an angle of inclination θ = 29 ° with a constant speed of 1.13 m/s by a steam winch (see Figure). The coefficient of kinetic friction between the block and the incline is 0.12. How much power must be supplied by the winch?
2. Relevant equations
T= uW/cos(theta)+u*sin(theta)
P=Fv
3. The attempt at a solution
T= .12(1400*9.8)/cos(29)+.12*sin(29)
T= 1765.0 N
P= FV
P= 1765*1.13
P= 1994.5 W
That equation does not look correct
Kajayacht
Sep29-08, 04:59 PM
wait do you mean the equation itself or I put in the values wrong?
LowlyPion
Sep29-08, 05:15 PM
wait do you mean the equation itself or I put in the values wrong?
That equation is incorrect.
Kajayacht
Sep29-08, 05:31 PM
Figured that much, but I was hopeful.
Could you give me a hint or something, I think I might now the equations I need but my notebook is at my dorm right now and my next class is about to start.
LowlyPion
Sep29-08, 05:54 PM
Figured that much, but I was hopeful.
Could you give me a hint or something, I think I might now the equations I need but my notebook is at my dorm right now and my next class is about to start.
Tension is going to equal the frictional resistance and the weight down the incline.
You don't need your notebook.
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