Driving a car

  • Thread starter helpme2012
  • Start date
  • #1
11
0

Homework Statement



You are driving your car and you heavily apply the brakes for a period of 2.1 seconds. The car keeps moving for a distance of 14.6m before it completely stops.

What is the acceleration (in m/s2) experienced by the car? Is it truly "acceleration"?


Homework Equations



5 kinematic equations

The Attempt at a Solution


I was using this : Δd=VfΔt-0.5aΔt2

14.6=0(2.1)-0.5a(2.12)
14.6= 0-0.5a(4.41)

I don't know what to do after that, I don't know what to do with the part of the equation with the acceleration. Am I even using the right kinematic equation?
 

Answers and Replies

  • #2
CompuChip
Science Advisor
Homework Helper
4,302
47
You are using the right one! Note how you have a single equation with just one unknown, a - which is exactly what you're after.
So much for the physics part, you need to pull out your mathematical skills now and solve the equation. First, try simplifying 0.5 * 4.41 and 0 - ....
 
  • #3
HallsofIvy
Science Advisor
Homework Helper
41,833
964
Notice the "0- " part. The acceleration will be negative. In everyday language we would call that "deceleration" but, technically, it is still a type of "acceleration".
 
  • #4
Evo
Mentor
23,202
3,013

Homework Statement



You are driving your car and you heavily apply the brakes for a period of 2.1 seconds. The car keeps moving for a distance of 14.6m before it completely stops.

What is the acceleration (in m/s2) experienced by the car? Is it truly "acceleration"?


Homework Equations



5 kinematic equations

The Attempt at a Solution


I was using this : Δd=VfΔt-0.5aΔt2

14.6=0(2.1)-0.5a(2.12)
14.6= 0-0.5a(4.41)

I don't know what to do after that, I don't know what to do with the part of the equation with the acceleration. Am I even using the right kinematic equation?
Copied.
 

Related Threads on Driving a car

  • Last Post
Replies
4
Views
2K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
7
Views
10K
  • Last Post
Replies
3
Views
6K
  • Last Post
Replies
1
Views
9K
  • Last Post
Replies
12
Views
817
  • Last Post
Replies
0
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
1
Views
8K
Top