Calculating Work to Pull a Skier Up a Slope at Constant Speed

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SUMMARY

The problem involves calculating the work required to pull a skier of mass 69.5 kg up a 30.1° slope over a distance of 59.1 m at a constant speed of 2.07 m/s. The force of gravity acting parallel to the slope is calculated as 341.57 N, leading to a total work of 20.186 kJ to overcome this force. The constant speed indicates that the work done does not depend on the speed itself, as per Newton's Second Law, meaning the required work remains the same regardless of the skier's velocity.

PREREQUISITES
  • Understanding of Newton's Second Law
  • Basic knowledge of trigonometry (sine function)
  • Familiarity with work-energy principles
  • Ability to perform unit conversions (e.g., Joules to kilojoules)
NEXT STEPS
  • Study the application of Newton's Second Law in various contexts
  • Learn about work-energy theorem and its implications in physics
  • Explore frictionless incline problems in classical mechanics
  • Investigate the effects of varying speeds on work done in different scenarios
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Students studying physics, particularly those focusing on mechanics, as well as educators looking for examples of work calculations in real-world applications.

Sheneron
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Homework Statement


A skier of mass 69.5 kg is pulled up a slope by a motor-driven cable.
a) How much work is required to pull him a distance of 59.1 m up a 30.1° slope (assumed frictionless) at a constant speed of 2.07 m/s?


The Attempt at a Solution


I started out this problem by finding out what that force of gravity parallel to the slope would be.
mgsin(30.1)=341.57 N

Then I figured I would find the total negative work that would be done for the whole slope so I multiplied that by 59.1m to get 20.186 kJ.

The thing I am not sure how to figure out is how much work is required to pull him up at 2.07 m/s. Because anything greater than 20.186kJ would just pull him up, but not necessarily at 2.07 m/s.

Also this answer alone counts as the right answer, but it can't be exactly right because its hasn't taken into account the desired velocity right?
 
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You did the problem absolutely right, the 2.07 m/s was just thrown in there to trick you. Because it is at a constant speed, Newtons Second Law says the forces must be equal. The 2.07 was an arbitrary value that the skier is brought to before the incline, it could have been 1000 with the same result.
 
I kind of had the inclination the whole time. So, it wouldn't matter what velocity he was traveling it would still be the same joules?
 

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