Force for uniform circular motion

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Homework Help Overview

The discussion revolves around a physics problem involving uniform circular motion, specifically focusing on the forces acting on an ice skater as she moves in a circular path after grabbing a rope. The problem requires calculating the force exerted by the rope and the ratio of this force to the skater's weight.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to calculate the force exerted by the rope using the formula for centripetal force. They express uncertainty regarding the calculation of the ratio of this force to the skater's weight and question the appropriate method to find this ratio.
  • Another participant suggests that the tension calculated in part (a) is indeed the force needed for the ratio but expresses confusion about how to correctly compute this ratio.
  • Subsequent posts indicate attempts to clarify the relationship between the force, mass, and gravitational acceleration.

Discussion Status

Contextual Notes

Participants are working within the constraints of a homework assignment, which may limit the information available for discussion. The original poster has indicated confidence in their calculation for part (a) but is seeking further clarification on part (b).

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[SOLVED] Force for uniform circular motion

Homework Statement


A 61.7 kg ice skater is moving at 3.55 m/s when she grabs the loose end of a rope, the opposite end of which is tied to a pole. She then moves in a circle of radius 0.545 m around the pole. The acceleration of gravity is 9.8 m/s^2.
a. Find the force exerted by the rope on her arms. Answer in units of kN.
b. Find the ratio of this tension to her weight.

Homework Equations


F=(mv^2)/r


The Attempt at a Solution


I got a using the above equation:
F=((61.7) * (3.55)^2)/.545
F=1426.74 N or 1.42674 kN
I know this is right for part a, I just don't understand what they are asking for part b or what equation to use. I would appreciate any help.
 
Last edited:
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Please help...I just need to figure out how I would start this. I understand now that the "tension" is the force that I calculated in (a) but I am unsure how to find the ratio of this tension to her weight (61.7 kg) i was thinking just diving 61.7/1.42674 but that does not seem right. I would greatly appreciate any help.
 
Got it...thanks anyway...--->1426.74/(61.7 * 9.81)=2.3572
 
Ratio is f/mg
 
Last edited:

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