How to calculate torque required to accelerate

In summary, to break the static coefficient of friction and cause the wheel to start turning, gearhead will need to generate a torque of 36.1N*m. To determine how much torque is required to accelerate at a rate of 1m/s^2, gearhead will need to generate a torque of 176.86N*m.
  • #1
gearhead
31
0
I have a bicycle that has a mass of 100kilograms with the rider on it. The wheels have a diameter of 26" or 0.722meters. How do i calculate how much torque is required to: 1.) break the static coefficient of friction and cause the wheel to start turning, and 2.) determine how much torque is required to accelerate at a rate of 1m/s^2?
 
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  • #2
Assuming no slipping, the torque, [itex]\tau[/itex], delivered to the wheels of radius, R, is related to the force, F, that pushes the vehicle by

[tex]\tau=RF[/itex]
 
  • #3
so then i must calculate the force of static friction on the bike first to determine the amount of torque required to overcome this. F=ma, f=100(9.8) = 980N*0.5(the static coefficient of friction)=Force of friction=490N. So then required torque is then, t=0.361m*490=176.86N*m of torque to counteract friction and cause the wheel to start turning.
 
  • #4
gearhead said:
I have a bicycle … How do i calculate how much torque is required to: 1.) break the static coefficient of friction and cause the wheel to start turning

Hi gearhead! :smile:

The wheel does not move relative to the ground, so the static friction to be overcome is only between the axle and the bearings.

For deformable wheels (eg rubber), there is also rolling resistance (loss of energy through deformation … it's what slows the Moon down!): see http://en.wikipedia.org/wiki/Rolling_resistance :wink:
 
  • #5
tiny-tim said:
... the static friction to be overcome is only between the axle and the bearings.
Ah, yes, that is a better interpretation of the question than what I was thinking of. Then gearhead will also need the radius of the axle.
 
  • #6
oh allright, thanks guys, so then theoretically any amount of torque you generate will accelerate you forward right?
 
  • #7
so then, i'll try to calculate the amount of torque required to accelerate the bike at 1m/s^2.
using
F=ma, F=(100kg)*(1m/s^2)=100Newtons.
T=R*F. T=(0.361m)*(100N)=36.1N*m of torque, right?
 

1. What is torque and why is it important for acceleration?

Torque is a measurement of the force that causes an object to rotate around an axis. It is important for acceleration because it is directly related to an object's rotational motion, which is one component of overall acceleration.

2. How do you calculate torque required for acceleration?

To calculate torque required for acceleration, you need to know the mass of the object, the distance from the axis of rotation to the point where the force is applied, and the angular acceleration. Then, you can use the formula: Torque = mass x distance x angular acceleration.

3. What units are used to measure torque?

Torque is typically measured in units of Newton-meters (Nm) or foot-pounds (ft-lb). These units represent the amount of force required to produce a certain amount of torque.

4. How does the direction of force affect torque?

The direction of the force applied to an object affects the direction of the torque. If the force is applied perpendicular to the axis of rotation, the torque will be at its maximum. If the force is applied parallel to the axis of rotation, the torque will be at its minimum.

5. Can you use torque to determine an object's acceleration?

Yes, torque can be used to determine an object's rotational acceleration. However, to calculate the overall acceleration of an object, you also need to consider the linear acceleration component, which is affected by other factors such as friction and air resistance.

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