Can you suggest a simple theory to explain the stability of a moving bicycle? You must explain why it is much more difficult to balance yourself on a bicycle that is at rest than on one that is rolling. (See "The Stability of the Bicycle," by David E. H. Jones, Physics Today, April 1970, p. 34.)

Simran Bhatia Grade: 11

        Can you suggest a simple theory to explain the stability of a moving bicycle? You must explain why it is much more difficult to balance yourself on a bicycle that is at rest than on one that is rolling. (See "The Stability of the Bicycle," by David E. H. Jones, Physics Today, April 1970, p. 34.)

5 years ago

Answers : (1)

Aditi Chauhan

askIITians Faculty

396 Points

							The stability of the bicycle is because of the angular momentum possessed by the wheel. Suppose a torque acts on the bicycle when it moves, this torque will be responsible for changing the direction of the angular momentum of wheels but not the magnitude. The angle say (θ)by which the angular momentum vector changes is given by:


It can be seen from the expression above that for larger value of initial angular momentum, the angle corresponding to change in angular momentum of wheel would be smaller. This proves that it will be harder for any external torque to change the direction of initial angular momentum of wheel, and the bicycle would maintain its balance.
Therefore one can now account for the fact that the fast moving bicycle is more stable than the slow one.