# Calculate Torque on Unicycle for Homework Statement

• SherlockOhms
In summary, the woman is able to generate a maximum torque of her weight by using her unicycle pedal.
SherlockOhms

## Homework Statement

A woman is riding a unicycle. The mass of the woman is: m(w)=66.0 kg,
the mass of the unicycle is: m(u)=5.40 kg, the diameter of the unicycle
wheel is: d = 55.0 cm, and the length of the unicycle crank is L =
11.0 cm

What is the maximum torque that the woman is able to
generate just by using her weight to push on the unicycle
pedal?

τ = r x F

## The Attempt at a Solution

So, the maximum force that she can exert on the unicycle is her weight i.e. her mass times g. To find the torque all you have to do is multiply the length of the crank by the weight. I'm just wondering though why this is correct. I mean her weight acts vertically downwards, directly above the centre of the unicycle wheel. By the cross product formula r x F = |r||F|Sin(θ). But isn't theta in this case 0? Implying that the torque is 0, which can't be correct. I may just be visualizing this incorrectly though. If someone could explain this it'd be great. I'll attach a diagram of what I'm visualizing. Thanks.

https://www.physicsforums.com/attachments/58119

Am I visualising this incorrectly?

Your diagram did not show the force acting on the pedal but other than that I think you are correct. I think the angle is between th radius and the force and this would be 90 deg and sin 90 = 1 so T = F X r

Yeah, I was thinking that initially but our lecturer seemed pretty sure that it was the length of the crank times the applied force. This makes I sense to me as the rider is applying the force to the pedals and not the crank itself.

It is the length of the crank times the force on the pedal. There is nothing magic about the pedal other than a way to get the force from the foot to the end of the crank.

Ohhh, ok. I see. Thanks man.

## 1. How do you calculate torque on a unicycle?

To calculate torque on a unicycle, you need to know the force applied and the distance from the point of application to the center of the wheel. The formula for torque is T = Fr, where T is torque, F is force, and r is the distance.

## 2. What units are used for torque?

Torque is typically measured in newton-meters (N*m) or foot-pounds (ft-lb).

## 3. What factors affect the torque on a unicycle?

The two main factors that affect torque on a unicycle are the force applied and the distance from the point of application to the center of the wheel. Other factors that may affect torque include the weight of the rider, the size and weight distribution of the unicycle, and the terrain being ridden on.

## 4. How is torque different from force?

Force refers to the push or pull that an object experiences, while torque refers to the ability of a force to cause rotational motion. In other words, torque involves both the magnitude of the force and the distance from the point of application to the center of rotation.

## 5. Why is torque important to consider in unicycle riding?

Torque is important to consider in unicycle riding because it affects the stability and control of the unicycle. A larger torque may require more effort to balance and control the unicycle, while a smaller torque may make it easier to maneuver. Additionally, understanding torque can help riders make adjustments to their riding technique and equipment for better performance.

• Introductory Physics Homework Help
Replies
5
Views
1K
• Introductory Physics Homework Help
Replies
2
Views
919
• Introductory Physics Homework Help
Replies
22
Views
3K
• Introductory Physics Homework Help
Replies
7
Views
3K
• Introductory Physics Homework Help
Replies
8
Views
3K
• Introductory Physics Homework Help
Replies
33
Views
10K
• Introductory Physics Homework Help
Replies
22
Views
2K
• Introductory Physics Homework Help
Replies
3
Views
1K
• Introductory Physics Homework Help
Replies
30
Views
2K
• Introductory Physics Homework Help
Replies
4
Views
1K