Circular Motion while learning to drive

[haha1234]

Homework Statement

While learning to drive,you are in a 1200 kg car moving at 20.0m/s across a large,vacant,level parking lot.Suddenly you realize you are heading straight toward the brick sidewall of a large supermarket and are in danger of running into it.The pavement can exert a maximum horizontal force of 7000N on the car.
Explain why you should expect the force to have a well-defined maximum value.

Homework Equations

The Attempt at a Solution

The answer state that the maximum value determined by the surface roughness.Why the roughness of the road make the force well-defined?

 

[Doc Al]

What kind of force do you think is stopping the car?

(What does this question have to do with circular motion?)

 

[haha1234]

What kind of force do you think is stopping the car?

(What does this question have to do with circular motion?)

ioc.
And i want ask another question,why the minimum distance required to avoid collision when not applying brakes and turning the steering wheel is twice as that of applying brakes and not turning the steering wheel?
Sorry for my poor English and I hope that you can understand what I mean.:shy:

 

[Doc Al]

ioc.

?

And i want ask another question,why the minimum distance required to avoid collision when not applying brakes and turning the steering wheel is twice as that of applying brakes and not turning the steering wheel?

Figure out the required distance in each case and see for yourself! Hint: When turning the wheel, the force is centripetal.

 

[HalfLostAndSearching]

The roughness of the road plays a significant role in determining the maximum value of force that can be exerted on the car. This is because the roughness of the road affects the amount of friction between the car's tires and the pavement. Friction is a force that opposes motion and is dependent on the roughness of the surfaces in contact. In this scenario, the pavement can exert a maximum horizontal force of 7000N on the car, which means that the friction force between the tires and the pavement cannot exceed this value. If the road surface is too smooth, the friction force may not be enough to stop the car from crashing into the wall. On the other hand, if the road surface is too rough, the friction force may exceed the maximum value and cause the car to skid or lose control. Therefore, the roughness of the road provides a well-defined limit for the maximum force that can be exerted on the car, ensuring the safety of the driver and passengers.