Direction of friction in a yoyo rolling on an inclined plane

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SUMMARY

The direction of friction in a yoyo rolling on an inclined plane is definitively directed downwards to prevent slipping. If friction were absent, the yoyo would rotate in a manner that causes the contact point to slip upwards on the incline. The analysis of moments about the center of the yoyo reveals the relationship between the applied force (F) and the static friction force (fs). Additionally, changing the winding direction of the string alters the dynamics, affecting the direction of the applied force.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with concepts of torque and moments
  • Knowledge of rolling motion dynamics
  • Basic principles of static friction
NEXT STEPS
  • Study the principles of torque in rotational dynamics
  • Learn about the effects of static friction on rolling objects
  • Explore the mechanics of inclined planes in physics
  • Investigate the implications of changing force application points in rolling motion
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Physics students, educators, and anyone interested in understanding the mechanics of rolling motion and friction in inclined planes.

dahoom102
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Homework Statement
In this problem why is the friction directed downwards not upwards? Shouldn't the velocity of the point of contact with the ground be zero and therefore mgsin = fs ? All of the problems i studied the friction was in the upward direction i just wanna know why is it different here.
Relevant Equations
F.B.D
Mgsin
fs
Screenshot_20210304-190909_Drive.jpg
 
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dahoom102 said:
In this problem why is the friction directed downwards not upwards?
If there was no friction, which way would the yoyo rotate? And, therefore, which way would the contact point of the yoyo tend to slip on the surface of the incline? Which way must friction act to prevent such slipping?
 
dahoom102 said:
In this problem why is the friction directed downwards not upwards?
Take moments about the centre of the yoyo. What does that tell you about F and fs?
What if the string were wound the other way around, so that F is applied above the centre?
 

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