• Support PF! Buy your school textbooks, materials and every day products Here!

Friction problem

  • Thread starter grief
  • Start date
  • #1
73
1
The question is:

A car is traveling at 50 mi/h on a horizontal highway. If the coefficient of static friction between road and tires on a rainy day is 0.10, what is the minimum distance in which the car will stop?

I know how to solve it using static friction, but I don't understand why only static friction is needed in the problem, and kinetic friction does not apply.
 

Answers and Replies

  • #2
789
0
What is static friction? A force which prevents any relative motion until its threshold is reached. So in order to keep the friction between the road and your tires, you must maintain a minimum acceleration. And once you find this acceleration, you can find the minimum distance it will take to stop.
 
  • #3
73
1
so does that mean, when I press the breaks, there is only static friction between the tires and the road?
 
  • #4
Päällikkö
Homework Helper
515
10
With (an ideal) ABS, I suppose, there's only static friction(?)
 
  • #5
Integral
Staff Emeritus
Science Advisor
Gold Member
7,198
55
That is correct, as long as your wheels are not skidding they maintain static friction with the road. Consider the difference between skidding and rolling.
 
  • #6
73
1
ohh, ok, I get it now. Thank you for the help
 

Related Threads for: Friction problem

  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
5
Views
1K
  • Last Post
Replies
4
Views
1K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
3
Views
13K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
20
Views
2K
  • Last Post
Replies
3
Views
940
Top