Calculating Angle and Height in Conservation of Energy Problem with Friction

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SUMMARY

The discussion focuses on calculating the angle θ of a slope using the law of conservation of energy in a friction-influenced scenario involving a 46 kg skier. The skier descends a 21.7 m slope, experiencing a kinetic friction force of 41 N, with initial and final speeds of 0.65 m/s and 7.19 m/s, respectively. The solution involves rearranging the conservation of energy equation to isolate sinθ, ultimately determining the angle to be approximately 12 degrees after calculating the height using energy conservation principles.

PREREQUISITES
  • Understanding of the law of conservation of energy
  • Familiarity with potential energy (PE) and kinetic energy (KE) equations
  • Knowledge of frictional forces and their impact on motion
  • Basic trigonometry, specifically the sine function
NEXT STEPS
  • Study the derivation of the conservation of energy formula in physics
  • Learn about calculating work done against friction in mechanical systems
  • Explore the relationship between angle, height, and distance in inclined planes
  • Review examples of energy conservation problems involving friction
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, as well as educators seeking to explain energy conservation principles in real-world scenarios involving friction.

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Homework Statement


A 46 kg skier slides down a slope 21.7 m long, incilned at an angle θ to the horizontal. The magnitude of the kinetic friction force is 41 N. The skier s initial speed is 0.65 m/s and the speed at the bottom of the slope is 7.19 m/s. determine the angle θ from the law of conservation of enegery. Air resistance is neglible


Homework Equations



PE=mgy, KE= 1/2mv^2, W=F*d, Ff=μmgsinθ

The Attempt at a Solution


My attemp at the equation was based on the law of conservation of energy with this resulting formula

(mgh+1/2mv^2-mgh-1/2mv^2)/Ff*d=sinθ

I can't figure out how to find the height without an angle or vice versa, i ve been trying to figure it out for the last little bit with no success. I feel like I m missing just one step
 
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TheMasterFool said:

Homework Statement


A 46 kg skier slides down a slope 21.7 m long, incilned at an angle θ to the horizontal. The magnitude of the kinetic friction force is 41 N. The skier s initial speed is 0.65 m/s and the speed at the bottom of the slope is 7.19 m/s. determine the angle θ from the law of conservation of enegery. Air resistance is neglible


Homework Equations



PE=mgy, KE= 1/2mv^2, W=F*d, Ff=μmgsinθ

The Attempt at a Solution


My attemp at the equation was based on the law of conservation of energy with this resulting formula

(mgh+1/2mv^2-mgh-1/2mv^2)/Ff*d=sinθ

I can't figure out how to find the height without an angle or vice versa, i ve been trying to figure it out for the last little bit with no success. I feel like I m missing just one step


How much work was done against friction during the slide?
 
Hey I think i figured it out, I took sin theta outta my energy conservation since it gave me the resisting force of 41N. I then used the energy conservation formula to find height and then O/H sin -1 to find my angle which turned out to be sig fig 12 degrees. It feels right but I guess I ll find out and post again.
 

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