why is it easy to balance a bike when it is moving than when it is stationary?

Question

According to the theory of relativity both senarios are comparable. Than why this difference???

Answer 1

This has nothing to do with relativity. Relativity relates frames of motion - the forces that act on your bike while it moves is not dependent on the frame chosen.

The reason a bike is easier to balance when moving relies upon the concept of angular momentum. When an object spins - in this case the wheels - it inherits a tendency to stay in place. Part of this is a direct result of Newton's first law of motion - paraphrased, it says "an object in motion tends to stay in motion, unless acted on by an outside force".

An identical effect is demonstrated by a top. A stationary top will immediately fall, but a spinning one will remain upright. The reason for this is a bit complicated - feel free to research this yourelf.

Also note that the spokes on a bike wheel are designed to help keep a bike upright. When spinning, they apply air resistance whenever the bike tilts. These forces are generated only when the bike is moving - again, relativity has nothing to do with balancing a bike.

Note: Gyroscopic action is not a proper term to apply here - in fact, gyroscopic action is not a term at all. It is true that a gyroscope and a bike wheel rely on the same principles; the principle happens to be called angular momentum.

Answer 2

Gyroscopic action in the wheels.
If you hold a bicycle wheel in two hands by the spindle, you can move it anywhere you like with ease.
If you get a friend to spin that wheel, as fast as possible, you will then find the wheel is reluctant to turn from side to side.
This reluctance is due to gyroscopic action.
Exactly the same action as keeps a spinning top upright whilst it is rotating.
I am sorry but I cannot for the life of me see where relativity comes in. I do not believe that it is relevant.
P.S.
I notice you say 'when the bike is moving'
The gyroscopic action does not require any forward movement, this does not even come into the equation.
The bike will be stable even whilst stationary on a treadmill or running conveyor, as long as the wheels are turning.
Neither does air affect this effect. A large number of racing bikes these days do not have spokes they have solid disc wheels.The gyroscopic effect is just as effective in a vacuum, we use the effect in geostationary satellites to ensure they always face earth and in deep space probes for stability obviously in vacuum.

Answer 3

Both scenarios are not really comparable, because in one, the wheels are spinning, and in the other, they're not. The spinning wheels make all the difference (as others pointed out).

There are training machines that let you place your bicycle onto some rollers so you can "ride" your bike without going anywhere (professional cyclists use these). There is nothing on these machines to keep the bikes from falling over sideways; yet the bikes stay upright because of the gyroscopic action of the spinning wheels.

Answer 4

When u r stationary the gravity acts upon u from the same direction all the time. Obviuosly, u wud not be able to resist the force of gravity for too long while on a bike n tryin balancin it....... But when u r movin, even in the staight line, the angle that the gravity acts upon changes every moment. Thus only the speed of the bike wud be enough to minimize the pull towards earth & u balance the bike properly !

Answer 5

Wwhat does the theory of Rel got to do with it?

There is a VECTOR= L the angular momentum of the spinning bicycle wheel that points in a constant direction. It is perpendicular to the plane of the wheel. (See the right hand rule). It resists having its direction changed. You must apply a TORQUE to change the angular momentum vector's direction.

If the wheel is not spinning, then there is NO vector L present to resist turning the wheel and gravity will easily cause it to fall over.

Answer 6

According to Kinetics Energy of the Bike has an front momentum,rectilinear motion.This keeps it on straight line.
Power = Force x velocipede
P=Fx V

Answer 7

Gyroscopic action in the wheels.
If you hold a bicycle wheel in two hands by the spindle, you can move it anywhere you like with ease.
If you get a friend to spin that wheel, as fast as possible, you will then find the wheel is reluctant to turn from side to side.
This reluctance is due to gyroscopic action.
Exactly the same action as keeps a spinning top upright whilst it is rotating.

Answer 8

due to the inertia of motion the bike has lesser tendency to tilt sideways when it is moving.