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A bicyclist of mass 70kg puts all his mass on each downward moving pedal as he pedals up a steep road. Take the diameter of the circle in which the pedals rotate to be0.40m , and determine the magnitude of the maximum torque he exerts about the rotation axis of the pedals.

Short Answer

Expert verified

Magnitude of maximum torque is 140N.m.

Step by step solution

01

Step 1: Given

  1. Mass of the bicyclist is 70kg
  2. Diameter of the circle in which the pedal rotates is 0.40m
02

Determining the concept

Firstly, find the force from mass and acceleration due to gravity. Then, using the formula for torque in terms of force and radius, find the torque.

Formulae are as follow:

τ=r×FF=mg

Where,

Ï„ is torque, m is mass, r is radius, F is force and g is acceleration due to gravity.

03

Determining the magnitude of maximum torque

First, find force as follows:

F=m×gF=70×9.8F=686N

Now, torque is found as follows:

τ=F×d2τ=686×0.42τ=137.2N.m

In two significant figures,

Ï„=140N.m

Hence, magnitude of maximum torque is 140N.m

Therefore, the formula for torque in terms of force and radius can be found to find the torque about the rotational axis of the pedals.

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