Power up and incline with friction

AI Thread Summary
A 1400 kg granite block is pulled up a 29° incline at a constant speed of 1.13 m/s, with a kinetic friction coefficient of 0.12. The tension in the winch is calculated using the equation T = uW/cos(θ) + u*sin(θ), resulting in a value of 1765.0 N. Power supplied by the winch is then determined using P = Fv, yielding 1994.5 W. There is a discussion about the correctness of the equation used for tension, with participants seeking clarification and hints for solving the problem. The conversation emphasizes the relationship between tension, friction, and weight on the incline.
Kajayacht
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Homework Statement


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?


Homework Equations


T= uW/cos(theta)+u*sin(theta)
P=Fv


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
 
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Kajayacht said:

Homework Statement


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?


Homework 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
 
wait do you mean the equation itself or I put in the values wrong?
 
Kajayacht said:
wait do you mean the equation itself or I put in the values wrong?

That equation is incorrect.
 
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.
 
Kajayacht said:
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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Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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