Question

A bicycle is being peddelled, then force of friction acts

• A. on front wheel in forward direction.
• B. on back wheel in backward direction.
• C. on front wheel in backward direction .
• D. on back wheel in forward direction.

Answer 1

Answer: (C), (D)

The correct options are
C on front wheel in backward direction .
D on back wheel in forward direction.

When we apply a torque on the rear wheel using the pedals, the wheel tries to push the ground in the backward direction thereby gaining a frictional force in the forward direction.
Now for the the front wheel we see that the only resistance to its motion is provided by the ground in the form of friction. This frictional force acts in the backward direction.
Note that the external torque provided at the axis of the rear wheel is not present for the front wheel.