1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Bike gear problem

  1. Nov 8, 2006 #1
    The rear wheel of a bicycle has a set of sprockets whcih vary in size. The chain hooks onto the sprockets, and when a pulling force is apply to the chain, the sprocket, hence the wheel turns. As any cyclist knows, when going up a hill, to maintain a constant velocity, it is better to use a lower gear, or larger sprocket. Why? In your answer, consider what the net torque is at constant velocity.

    Ok so obviously, the larger the sprocket the easier it is to pedal, but I'm not quite sure why...I dont even know if that will apply here or not.
     
  2. jcsd
  3. Nov 8, 2006 #2
    Any suggestions?
     
  4. Nov 8, 2006 #3
    to explain in terms of torque...if the radius is increasing the force must decrease...causing there less force to be exerted on the pedals if the radius is large....soo should there be no net torque on the bike? how does this relate in terms of constant velocity?
     
  5. Nov 8, 2006 #4

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    My ankles are weaker than my wrists. It is about torque, but not less force. When going uphill, gravity is trying to pull you back down; to counteract it and move at a steady pace, without slowing because of that hill, you've got to apply more torque to keep yourself moving ahead. The idea is to apply the same force, or not much more, as when riding level, but with the increase in radius, the torque will increase even at that same force, and this increase in torque will result in keeping you from slowing, i.e., moving at constant speed rather than decelerating.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Bike gear problem
  1. Bike Problem Help (Replies: 2)

  2. Bike race problem (Replies: 1)

Loading...