[abhay_singh619]

In circus bikers move on bikes in a death well horizontally as well as verically but do not fall. Kindly explain the reason and tell what are the forces acting on them .

[ballengerb1]

It is basically centrifical force. They don't go around horizontally until they build up speed. In a tight circle that speed builds centrifical force or Gs. Gs become an artificial gravity that pushes them out in a straight line, in this case the floor of the cage. If they hit the breaks the speed would drop as would the centrifical force, they would fall in the direction of the only remaining force, gravity straight down.

[Capuchin]

Centrifical? You mean Centrifugal? It's slightly misleading to think of things in terms of centrifugal force, because it doesn't exist in the stationary reference frame, only in the biker's reference frame.

You need to consider what is happening in terms of centripetal force. Centripetal force is the force that the track exerts on the bike. This force accelerates the bike toward the center of the circle. This is what keeps the biker carrying on in the same circle.

I don't think ballenger very well identified the force that opposes gravity here. This is due to the shape of the track, it's like a bowl. Because the bikes want to continue in a straight line, and want to oppose the centripetal force (this is what the bikers feel as a centrifugal force), then They can minimise this force by being on the biggest possible circle, this means that it must be higher up on the bowl, this is what pushes them up against gravity. (the faster they go, the harder it is for them to go on a small circle, as the force increases).

Hope this clears it up, please ask if you need further help :)

[ballengerb1]

Yep, sorry for the poor phonetic spelling of centrifugal. It doesn't really exist but is often used to simply the explanation of forces a person senses. An object traveling in a circle behaves as if it is experiencing an outward force. This force, known as the centrifugal force, depends on the mass of the object, the speed of rotation, and the distance from the center. The more massive the object, the greater the force; the greater the speed of the object, the greater the force; and the greater the distance from the center, the greater the force.

[Capuchin]

and the greater the distance from the center, the greater the force.

I disagree. The death wall works by pushing the rider out to the biggest circle in order to minimise force.

But you wouldn't do any calculating with centrifugal force, Because more often you would be in the stationary reference frame.

[blablabla2]

I don't know if this helps with your question, but you can watch it work at home by doing the following: Fill a clear glass half way with water and hold it out at arms length, now pirouette while watching the water. You can see it climbing the wall of the glass and you can tilt the glass to the horizontal position without spilling a drop. That effect is the same experienced by the rider. You can also hold a cup of water by the mouth with your finger tips and swing your arm like a windmill, on the top of the swing the cup is upside down yet the force is stronger than gravity so the water stays in place.
You can also put a marble in a large plastic bowl and spin the marble like a roulette wheel and you can see it doesn't go straight to the bottom and stop, but it goes round and round just like the rider.
If your lucky and have a Hamster ball, your can put the marble in that and watch how it reacts to different speeds.
You can also watch these cool videos:
http://youtube.com/watch?v=epqSuvrBWQs
http://youtube.com/watch?v=wiZoVAZGgsw&feature=related