I was usually told that in a uniform circular motion the work is 0 because the force is every instant perpendicular to the displacement. However, studying the motion i noticed that there is a force acting on the moving object that is always parallel to the displacement and perpendicular to the radius to the circumference ( it's the force that continuously changes the velocity vector). Why it doesn't do work ?

enter image description here


closed as unclear what you're asking by stafusa, John Rennie, sammy gerbil, ZeroTheHero, Yashas Sep 22 '18 at 13:25

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    $\begingroup$ What you have labeled F in the diagram is not a force, it is a velocity. $\endgroup$ – Dale Sep 22 '18 at 8:09
  • $\begingroup$ See Work in circular motions $\endgroup$ – sammy gerbil Sep 22 '18 at 11:38

The force is not tangential. It is always radially inward.

Thus, it is perpendicular to the velocity vector and does no work.

(Image source : Wikipedia)

Note that the direction of force in this image is exactly opposite to the radius vector.

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    $\begingroup$ However, if the velocity vector constantly changes shouldn't there be a force ? $\endgroup$ – Koinos Sep 22 '18 at 8:13
  • $\begingroup$ @Koinos The force (not shown in figure) is in radially inward direction $\endgroup$ – Archisman Panigrahi Sep 22 '18 at 9:14

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