Calculating the Length of a Driveway Using the Work-Kinetic Energy Theorem

  • Thread starter Thread starter BadCo55
  • Start date Start date
  • Tags Tags
    Energy Theorem
AI Thread Summary
To calculate the length of the driveway, the work-kinetic energy theorem is applied, where the net work done on the car equals its change in kinetic energy. The car's initial kinetic energy is zero since it starts from rest, and the final kinetic energy is determined using its mass and speed at the bottom of the driveway. The work done against friction is calculated using the friction force and the distance traveled, which is negative due to the opposing direction of friction. The equation Wnet = KE leads to solving for the length of the driveway. A complete solution requires showing all calculations to clarify the process.
BadCo55
Messages
3
Reaction score
0

Homework Statement


A 2.1x103 kg car starts from rest at the top of a driveway that is cooped at an angle of 20.0° with the horizontal. An average friction force of 4.0 x 103 N impedes the car's motion so that the car's speed at the bottom of the driveway is 3.8 m/s. What is the length of the driveway.


Homework Equations


Wnet = KE

In other words: Work = m1v1/2 - m2v2/2

Work = force x distance


The Attempt at a Solution



Please give me some work along with the answer so I can understand how to complete the problem.
 
Physics news on Phys.org
Hi BadCo55! Welcome to PF! :wink:

Show us what you've tried and where you're stuck, and then we'll know how to help! :smile:
 
That's the thing, I really don't know how to start...
 
start with the work-energy theorem
 
Would it be d = -0.2625 ? Since it's frictional force I put -4.0x10^3
 
(just got up :zzz:)

please show your calculations :smile:​
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Work-Kinetic Energy Theorem problem
Replies
2
Views
3K
Work and kinetic theorem problem using friction
Replies
8
Views
24K
Finding length of driveway (work-kinetic energy theorem)
Replies
3
Views
14K
Homework Help: Work-Kinetic Energy Theorem
Replies
3
Views
3K
How would you go about solving this Work-kinetic energy thorem?
Replies
1
Views
3K
How Do You Calculate the Speed of a Car Down an Inclined Driveway with Friction?
Replies
6
Views
3K
Work energy KE theorem for a book being lifted up in a gravitional field
Replies
18
Views
2K
Work-Kinetic Energy Theorum Problem
Replies
3
Views
8K
A block dropping onto a spring system
2
Replies
58
Views
2K
Lifting an object, kinetic energy, work and forces
Replies
11
Views
5K

Hot Threads

Recent Insights

Back
Top