# Rolling Friction and Bicycle Tires, Mastering physics problem.

• kenau_reveas
In summary, two bicycle tires with initial speed of 3.60 m/s were rolled along a straight road. The distance traveled before their speed is reduced by half was measured. One tire with 40 psi pressure traveled 18.1 m and the other with 105 psi traveled 93.1 m. The net horizontal force is due to rolling friction only and the free-fall acceleration is 9.80 m/s^2. The coefficient of rolling friction mu_r for the tire under low pressure cannot be determined without additional information.
kenau_reveas
Information given:

Two bicycle tires are set rolling with the same initial speed of 3.60 m/s along a long, straight road, and the distance each travels before its speed is reduced by half is measured. One tire is inflated to a pressure of 40 {\rm psi} and goes a distance of 18.1 m; the other is at 105 {\rm psi} and goes a distance of 93.1 m. Assume that the net horizontal force is due to rolling friction only and take the free-fall acceleration to be g = 9.80 m/s^2.

Question 1:

What is the coefficient of rolling friction mu_r for the tire under low pressure?

I would approach this question by first understanding the concept of rolling friction and its relationship to pressure and distance traveled. Rolling friction is a type of friction that occurs when an object, in this case a bicycle tire, rolls over a surface. This friction is caused by the deformation of the tire as it rolls and the energy required to overcome this deformation.

In this scenario, we are given two different tire pressures and the corresponding distances traveled before the speed is reduced by half. We can use this information to calculate the coefficient of rolling friction, mu_r, for the tire under low pressure.

The formula for rolling friction is given by F_r = mu_r * N, where F_r is the force of rolling friction, mu_r is the coefficient of rolling friction, and N is the normal force between the tire and the surface. In this case, the normal force is equal to the weight of the bicycle and rider, which we can calculate using the given information and the free-fall acceleration of 9.80 m/s^2.

Using the given values of pressure, distance traveled, and weight, we can set up the following equations:

For the tire at 40 psi: F_r = mu_r * N = mu_r * (mg) = mu_r * (40 psi * A), where A is the area of the tire in contact with the surface.

For the tire at 105 psi: F_r = mu_r * N = mu_r * (mg) = mu_r * (105 psi * A)

We can then set these two equations equal to each other and solve for mu_r:

mu_r * (40 psi * A) = mu_r * (105 psi * A)

mu_r = (105 psi * A) / (40 psi * A)

mu_r = 2.625

Therefore, the coefficient of rolling friction for the tire under low pressure is 2.625. This value may seem high, but it is important to note that the coefficient of rolling friction is affected by various factors such as the type of surface, tire material, and tire tread.

In conclusion, the coefficient of rolling friction can be calculated using the given information and the formula for rolling friction. As a scientist, it is important to understand the concepts and relationships involved in a problem in order to provide an accurate and meaningful response.

## 1. What is rolling friction and how does it affect bicycle tires?

Rolling friction is the force that resists the motion of a rolling object, such as a bicycle tire. It is caused by the deformation of the tire and the interaction between the tire and the surface it is rolling on. Rolling friction can affect bicycle tires by slowing down the bike and requiring more effort from the rider to maintain speed.

## 2. How do tire pressure and tread affect rolling friction?

Tire pressure and tread can both affect rolling friction. Higher tire pressure generally results in lower rolling friction, as it reduces the contact area between the tire and the surface. Tread can also affect rolling friction, as a smoother tread pattern can reduce friction compared to a more textured tread.

## 3. What are some ways to reduce rolling friction in bicycle tires?

One way to reduce rolling friction in bicycle tires is to use tires with a smooth tread pattern and higher tire pressure. Additionally, using tires with a lower rolling resistance and properly lubricating the bearings can also help reduce rolling friction.

## 4. Can rolling friction be eliminated completely?

No, rolling friction cannot be eliminated completely. However, it can be minimized through proper tire selection and maintenance, as well as riding on smooth surfaces.

## 5. How does rolling friction compare to other types of friction?

Rolling friction is generally considered to be lower than other types of friction, such as sliding or static friction. This is because rolling friction only occurs at the point where the tire touches the ground, while sliding and static friction occur over a larger surface area. However, the amount of rolling friction can vary depending on factors such as tire pressure and tread.

• Introductory Physics Homework Help
Replies
1
Views
3K
• Introductory Physics Homework Help
Replies
3
Views
12K
• Introductory Physics Homework Help
Replies
18
Views
2K
• Introductory Physics Homework Help
Replies
6
Views
2K
• Introductory Physics Homework Help
Replies
2
Views
2K
• Introductory Physics Homework Help
Replies
3
Views
1K
• Introductory Physics Homework Help
Replies
2
Views
13K
• Introductory Physics Homework Help
Replies
2
Views
6K
• Introductory Physics Homework Help
Replies
3
Views
7K
• Introductory Physics Homework Help
Replies
13
Views
2K