Pushing a car & rolling resistance of tires

In summary, the rolling resistance coefficient of a normal car tire on asphalt is 0.03. This means that in order to get a 1000kg car rolling, a force greater than 294 N would need to be applied. If the car was already in motion at 3m/s, it would come to a stop in approximately 10.2 seconds due to the rolling resistance. The coefficient of rolling resistance is lower than the coefficient of static friction, which is why a car can easily keep moving once it is in motion.
  • #1
Hope Lansing
7
0
I just want to know if I am understanding this correctly.

I am wondering what effect the rolling resistance has on the motion of a car when pushed, or when rolling to a stop. The mass of the car is 1,000kg.

I looked up on a table to find the rolling resistance coefficient of a normal car tire on asphalt and got .03 so that is the value I am using.

Frr = .03 * 1,000kg * 9.8m/s² = 294 N

a = 294 N / 1,000 kg = .294m/s²

Question 1 :

Does this mean that if a 1,000kg car is at rest in nuetral, and I want to get that car rolling, I would need to apply a force greater than 294 N before the car would even begin to roll?

Question 2 :

If this car was already in motion at say, 3m/s, would it come to a stop in about 10.2 seconds? (t = 3m/s / .294m/s² = 10.2s)

I am ignoring any other sources of friction(ball bearings, etc), and the asphalt is perfectly level.

Any help would be greatly appreciated. Thank you.
 
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  • #2
That is a reasonable number for rolling resistance, which relates to the coefficient of dynamic friction. It would take more to get the car started.

Think of a locomotive, which could never start a train of cars at the same time because the coefficient of static friction is too high. But because it only has to start one car at a time, it has no trouble keeping them moving.
 
Last edited:

1. What is rolling resistance?

Rolling resistance is the force that opposes the motion of a tire as it rolls on a surface.

2. How does rolling resistance affect pushing a car?

Rolling resistance plays a significant role in the effort required to push a car. The higher the rolling resistance, the more effort will be required to move the car.

3. What factors contribute to rolling resistance?

There are several factors that contribute to rolling resistance, including tire design, tire pressure, road surface, and weight of the vehicle. Tires with a larger surface area, lower pressure, and softer rubber tend to have higher rolling resistance.

4. Can rolling resistance be reduced?

Yes, rolling resistance can be reduced by choosing tires with lower rolling resistance, maintaining proper tire pressure, and keeping the vehicle's weight to a minimum.

5. How does rolling resistance affect fuel efficiency?

Rolling resistance can have a significant impact on fuel efficiency. Higher rolling resistance means the engine has to work harder to move the car, resulting in lower fuel efficiency. By reducing rolling resistance, fuel efficiency can be improved.

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