How Much Static Friction is Needed for a Penny to Stay on a Rotating Record?

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SUMMARY

The minimum coefficient of static friction required for a penny to remain on a rotating record at 33.5 RPM with a diameter of 0.3 meters is determined using the formula for centripetal force. The penny experiences a centripetal acceleration directed towards the center of the record, which must be counteracted by the static frictional force. The necessary calculations involve understanding the relationship between rotational speed, radius, and frictional force to prevent sliding.

PREREQUISITES
  • Understanding of centripetal force and acceleration
  • Familiarity with static friction and its coefficient
  • Basic knowledge of rotational motion
  • Ability to apply Newton's laws of motion
NEXT STEPS
  • Calculate the centripetal acceleration for objects in circular motion
  • Explore the relationship between angular velocity and linear speed
  • Study the derivation of the static friction coefficient formula
  • Investigate real-world applications of static friction in rotating systems
USEFUL FOR

Physics students, educators, and anyone interested in the principles of motion and friction in rotational systems.

DoctorB2B
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Homework Statement


What is the minimum coefficient of static friction necessary to allow a penny to rotate without sliding off a 33.5rpm record (diameter of these old-fashioned records is 0.3), when the penny is placed at the edge of the record. Ignore the size of the penny.

The Attempt at a Solution


I know the equation to determine the static friction coefficient. However, I am clueless as to how to proceed from here.
 
Physics news on Phys.org
Which force slides off the penny from the record? What is its magnitude?
What is the direction and magnitude of the frictional force?
 

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