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Do these forces cancel out each other? If yes, how is forward motion initiated?

Also, in this situation, since friction between the road and the wheels is enabling motion, which force is opposing the motion?


1 Answer 1


No they do not cancel.

The frictional force on the front wheel is that required to overcome bearing friction etc so the wheel rotates.

The back wheel has sufficient friction to match the input power by the rider plus bearing friction etc.

  • $\begingroup$ Okay... so the forward force is the friction between the wheel and the road, right? Which forces can now resist the motion of the cycle? $\endgroup$ Jun 1, 2020 at 7:41
  • $\begingroup$ @RichieHarvy This looks like you are drifting away from the original question. $\endgroup$
    – Solar Mike
    Jun 1, 2020 at 7:42
  • $\begingroup$ You’ve answered my question. I just wanted to know sources of resistance for the motion. $\endgroup$ Jun 1, 2020 at 8:24
  • $\begingroup$ @Richie, you should really be able to work this out for yourself. What do you think would resist motion? Have you ever cycled a bike? $\endgroup$
    – Transistor
    Jun 1, 2020 at 10:08
  • $\begingroup$ @Transistor into a headwind :) $\endgroup$
    – Solar Mike
    Jun 1, 2020 at 10:34

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