What is the direction of force of friction on a bicycle on front and back wheel while paddling?
The direction of the force of friction on a bicycle differs between the front and back wheel while pedaling.
On the front wheel: When you pedal a bicycle, the force you exert on the pedals causes the front wheel to rotate. As a result, the direction of the force of friction on the front wheel opposes the motion of the bike. So, the force of friction on the front wheel acts backward or in the opposite direction to the forward motion of the bicycle.
On the back wheel: The force you apply to the pedals transfers through the chain and causes the back wheel to rotate. In this case, the force of friction on the back wheel aids the motion of the bike. Consequently, the force of friction on the back wheel acts forward or in the same direction as the bicycle's motion.
To understand the direction of the force of friction, you can use the "opposite direction rule." This rule states that the force of friction always acts in the opposite direction to the direction of the applied force or the direction of motion. As a result, the friction force on the front wheel opposes the motion, while the friction force on the back wheel aids the motion.