Homework Help: Force exerted on the pedals ?

1. Oct 19, 2006

juliorgonzalez

force exerted on the pedals...???

-) A cyclist intends to cycle up a 7.00° hill whose vertical height is 122 m. Assuming the mass of bicycle plus person is 76.2 kg, calculate how much work must be done against gravity. I got this part by multipling the (m)(g)(d)= 91100
If each complete revolution of the pedals moves the bike 5.00 m along its path, calculate the average force that must be exerted on the pedals tangent to their circular path. Neglect work done by friction and other losses. The pedals turn in a circle of diameter 34.6 cm.
I really have no idea . so if u can help me with that
thanx

2. Oct 19, 2006

quinn

Think about it. You know the required force at the wheels,.. and 1 rev of the pedel = 5 m,.. total path is known,... divide to get the amount of force at the wheels per 1 rev of the pedels,...next use torque conversion to get force at pedals,.. remember 5 m is the outer lever distance,.. so the pedel requires more force than at the wheels