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

Work-Energy Theorem Problem

  • #1

Homework Statement



A driver in a car is on a level road traveling at a speed of "v". He puts on the brakes and they lock and skid rather than roll. I have to use the Work-Energy Theorem to give an equation for the stopping distance of the car in terms of "v". the acceleration of gravity "g" and the coefficient of kinetic friction "u(k)" between the tires and the road.


Homework Equations



W = EK(f) - EK(i)

The Attempt at a Solution



I attempted to use various formulas I have that use friction and gravity but came up to no success. I am hoping someone else knows what they are doing.
 

Answers and Replies

  • #2
PhanthomJay
Science Advisor
Homework Helper
Gold Member
7,144
486

Homework Statement



A driver in a car is on a level road traveling at a speed of "v". He puts on the brakes and they lock and skid rather than roll. I have to use the Work-Energy Theorem to give an equation for the stopping distance of the car in terms of "v". the acceleration of gravity "g" and the coefficient of kinetic friction "u(k)" between the tires and the road.


Homework Equations



W = EK(f) - EK(i)

The Attempt at a Solution



I attempted to use various formulas I have that use friction and gravity but came up to no success. I am hoping someone else knows what they are doing.
You have identified the work done in your formula. What force does this work? How do you calculate it? What is the definition of work?
 
  • #3
The frictional force is the force doing this work. So W = -F(friction)*x. And F(friction) = u(k)mg. So -u(k)mg*x = 0 - (1/2)mv^2 ... and solve for x?
 
  • #4
PhanthomJay
Science Advisor
Homework Helper
Gold Member
7,144
486
The frictional force is the force doing this work. So W = -F(friction)*x. And F(friction) = u(k)mg. So -u(k)mg*x = 0 - (1/2)mv^2 ... and solve for x?
Looks good!
 
  • #5
Thank you so much. You were extremely helpful.
 

Related Threads on Work-Energy Theorem Problem

  • Last Post
Replies
5
Views
4K
  • Last Post
Replies
14
Views
8K
  • Last Post
Replies
5
Views
1K
  • Last Post
Replies
1
Views
440
  • Last Post
Replies
2
Views
845
  • Last Post
Replies
6
Views
3K
  • Last Post
Replies
9
Views
5K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
14
Views
2K
  • Last Post
Replies
12
Views
2K
Top