Power due to the force applied to the block by the cable?

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SUMMARY

The discussion centers on calculating the power exerted by a cable on a 2600 kg granite block being pulled up a 36.87-degree incline at a constant speed of 1.07 m/s. The initial calculations incorrectly assumed an acceleration of 5.88599 m/s², leading to an erroneous force of 15303 N. The correct approach involves recognizing that the block moves at constant speed, implying zero acceleration, and recalculating the net force as 10201 N. Consequently, the power output is accurately determined to be 21810.9 Watts.

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  • Understanding of Newton's laws of motion
  • Knowledge of frictional forces and coefficients
  • Familiarity with power calculations in physics
  • Basic trigonometry for resolving forces on an incline
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  • Study the concept of kinetic friction and its applications
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This discussion is beneficial for physics students, mechanical engineers, and anyone interested in understanding the dynamics of forces acting on objects on inclines.

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A 2600 kg block of granite is pulled up an incline which is 36.87 degrees off of the horizontal at a constant speed of 1.07m/s by a cable and winch. The coefficient of kinetic friction between the block and the incline is 0.25. What is the power due to the force applied to the block by the cable?

I started this problem by finding the acceleration of the block which is sin(36.87) *9.81=5.88599m/s^2

This times the mass is the force pulling up. = 15303 N

Next i found the frictional force which is N * u
so cos(36.87) * 9.81 * 2600 * .25 = 5101 N

I subtracted the force pulling up by the frictional force and multiplied it by the velocity 15303-5101 = 10201 * 1.07 = 10916 W

where did i go wrong because this is not the answer. thanks
 
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I think you mistake was the value of acceleration. When that block move with constant speed, the acceleration = 0.

Once you figured out the some of the forces, you can plug you number into the equation to find your work. It is Force multiplied by distance. In this case, you can assume that this system working in 1 second, so you can get the distance is equal to 1.07m.
Then plug in the W divided by the differences in time to get power. The time is 1 second because we assumed that this things happened in 1 sec.

Is the answer 21810.9 Joule/s? That's what i got.
 

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