Gravitational ep in a uniform field

AI Thread Summary
The problem involves calculating the change in gravitational potential energy for a 10.0 kg box sliding down a 15.0 m ramp inclined at 20.0 degrees, with a friction force of 40.0 N. The initial attempt calculated work done against friction as 563.8 J, but the correct change in gravitational potential energy is -503 J. To find this, the formula V = mgh should be used, requiring the initial height to be determined. The discussion emphasizes the importance of correctly applying gravitational potential energy concepts in physics problems. Understanding the relationship between work, energy, and friction is crucial for accurate calculations.
kelly242
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Homework Statement


A 10.0 kg box is slid down15.0 m along a 20.0o ramp. The force of friction is 40.0 N. What is the change in the gravitational potential energy of the box?

Homework Equations



W=Fdcos of theta

The Attempt at a Solution


W=(40 N)(15 m)(cos 20)
=563.8J
The actual answer is -503 J...
 
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Try:

V = mgh

Then just figure out what the initial height is.
 

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