Dynamic motion involving pulleys and friction.

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SUMMARY

The discussion centers on solving a dynamics problem involving pulleys and friction, specifically addressing the forces acting on mass C and the relationships between the forces. The user initially calculated the force of friction incorrectly, leading to a mass of 1.8 kg, which was identified as incorrect. The correct approach involves using the equation FfB = MC(9.8 - aA) and recognizing the need for an additional equation to solve for two unknowns. Participants suggest applying Newton's second law, F = ma, for masses A and B to derive the necessary equations.

PREREQUISITES
  • Understanding of Newton's laws of motion, particularly F = ma.
  • Familiarity with dynamics problems involving pulleys.
  • Knowledge of frictional forces and their calculations.
  • Basic algebra skills for solving equations with multiple variables.
NEXT STEPS
  • Study the principles of pulley systems in dynamics.
  • Learn how to apply Newton's second law to multi-body systems.
  • Explore friction calculations in dynamic scenarios.
  • Practice solving complex dynamics problems with multiple unknowns.
USEFUL FOR

Students studying physics, particularly those focusing on dynamics and mechanics, as well as educators looking for examples of problem-solving in pulley systems.

DaftCrunk
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Homework Statement


http://img689.imageshack.us/img689/2315/dynamicsproblem.jpg"

Homework Equations




The Attempt at a Solution



FC = FfB
mC * 9.81 = (6.0)(9.81)(0.30)
mC = 1.8 <---- :(

Obviously that was wrong haha. I then tried to figure out how the pulley affects the relationships of the forces, and figured:

FfB = MC(9.8-aA)
17.6 = MC(9.8-aA) <-----One equation, two unknowns. Need another equation, assuming this one is correct.
 
Last edited by a moderator:
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Welcome to PF!

Hi DaftCrunk! Welcome to PF! :smile:
DaftCrunk said:
… Need another equation, assuming this one is correct.

Yup! … try F = ma for A-and-B. :wink:
 

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