What is the Work Done in Circular Motion?

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SUMMARY

The work done on a body moving in circular motion at a constant angular speed \(\omega\) in a horizontal circle of radius \(r\) is zero. This conclusion is based on the fact that the centripetal force, which acts towards the center of the circle, is always perpendicular to the direction of motion. Consequently, since the displacement in the direction of the force is zero, the work done remains zero throughout one complete revolution.

PREREQUISITES
  • Understanding of circular motion dynamics
  • Familiarity with centripetal force concepts
  • Knowledge of work-energy principles
  • Basic proficiency in physics equations, specifically \(W=F \cdot s\)
NEXT STEPS
  • Study the implications of centripetal force in different motion scenarios
  • Explore the relationship between kinetic energy and work in circular motion
  • Investigate the effects of varying angular speeds on work done
  • Learn about non-uniform circular motion and its energy considerations
USEFUL FOR

Students studying physics, educators teaching circular motion concepts, and anyone interested in the principles of work and energy in rotational dynamics.

songoku
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Homework Statement


A body of mass m moves at constant angular speed \omega in a horizontal circle of radius r. What is the work done on the body in one revolution?

a. zero

b. 2\pi mr^2\omega ^2

c. \pi mr^3\omega ^3

d. mr^2 \omega ^2

e. mr^2 \omega ^2 /2

Homework Equations


W=F.s

The Attempt at a Solution


Because the displacement is zero, then the work done is zero?

Thanks
 
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What direction is the force on the body? What direction does the body move?

Or: Consider the change in the body's kinetic energy.
 
Yup. Another way to see it is that the centripetal force does not change the energy of the body.
 
Yes. You must look at the directions of the centripetal force, and the direction of velocity, and you find your answer.
 
Hi all

The direction of centripetal force is towards the center of circle and direction of motion is tangential to the circle.
So, it means that the work done is always zero because the force is perpendicular to the direction of motion?

Thanks
 
songoku said:
The direction of centripetal force is towards the center of circle and direction of motion is tangential to the circle.
So, it means that the work done is always zero because the force is perpendicular to the direction of motion?
Right!
 

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