Why can you exert a greater force on the pedals of a bike if you pull up on the handlebars?
Does it have anything to do with one of Newton's 3 laws? I'm not sure how to approach this question.
Stand on a scale and push on the ceiling :)
Third law. Force by man up on bars --> force down on man
Sum forces on the man who is not accelerating up or down
m g down + handlebar force down
force up on man = pedal force
net force = 0 so no change of momentum (F = m a = 0)
so
0 = m g down + handlebar force down - pedal up
so
pedal force UP on man = mg + handlebar force
so third law, equal and opposite force DOWN on pedal = m g + handlebar force
Thank you very much!
You are welcome.
Yes, the principle you are referring to is one of Newton's laws of motion. Specifically, it is related to Newton's third law of motion, which states that for every action, there is an equal and opposite reaction.
In the case of riding a bike, when you pull up on the handlebars, you are creating an upward force on the bike. According to Newton's third law, the bike exerts an equal and opposite force back on you. This force from the bike acts through the pedals, allowing you to exert a greater force on them.
When you pull up on the handlebars, the opposing force between you and the bike enhances the normal force that the pedals apply to your feet. The normal force is the force exerted by a surface perpendicular to it, in this case, the force exerted by the pedals on your feet. As the normal force increases, so does the friction between your feet and the pedals, providing more traction and allowing you to exert a greater force on the pedals.
To summarize, when you pull up on the handlebars, Newton's third law states that the bike exerts an equal and opposite force back on you. This force enhances the normal force between your feet and the pedals, allowing you to exert a greater force on the pedals.