What creates the reaction force in a vertical circle?

[daveyavey]

Hey, Simply I want to figure out what produces the reaction force, in this picture i drew, a reaction force appears directing in the same direction as the weight force, any ideas why? Sorry for the bad drawing

The example shows a cyclist going around a loop (upsidedown)

 

[Doc Al]

The track exerts a force on the bike.

 

[daveyavey]

The track exerts a force on the bike.

Oh... its that simple... sorry haha

 

[Astronuc]

Gravity is always acting downward, but there is a centripetal force related to mv²2/r, where m is the mass moving at tangential speed v on a circular path of radius r. The centripetal force acts normal to the tangential velocity v.

See - http://hyperphysics.phy-astr.gsu.edu/hbase/newt.html#strmas

http://hyperphysics.phy-astr.gsu.edu/hbase/circ.html

 

[Doc Al]

Oh... its that simple... sorry haha

Yep. The combination of the force of the track and the weight of the bike create the centripetal force that keeps it going in a circle.