Car accelerating on ramp - power of engine

Click For Summary

Homework Help Overview

The problem involves a car accelerating up a ramp at a specified rate, with a focus on understanding the relationship between the power output of the engine and the kinetic energy of the car. The ramp is inclined at a small angle, and external forces such as friction and air resistance are neglected.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between power, kinetic energy, and potential energy, questioning how energy is distributed in the absence of friction. Some explore the method of using kinematics to derive the final speed and calculate the ratio of kinetic energy to total energy.

Discussion Status

There is a mix of exploratory attempts and clarifications regarding energy distribution. Some participants have arrived at a numerical answer, while others are questioning the validity of their methods and whether the approach will consistently yield correct results under the given conditions.

Contextual Notes

Participants note the absence of friction and air resistance as a key assumption in their discussions, which influences their reasoning about energy conservation and the distribution of power. There is also mention of the problem being a review for an upcoming test.

physstudent1
Messages
267
Reaction score
1

Homework Statement



A car accelerates at 1 m/s^2 up a ramp which makes an angle of 5 degrees with the horizontal. Ignoring friction and air resistance what fraction of the power the engine puts into the car's motion goes into the car's kinetic energy?

Homework Equations





The Attempt at a Solution



I don't know how to attempt this problem I know the answer is 54% because this is a review problem for my test which is coming up, but how is power related to kinetic energy?
 
Physics news on Phys.org
Power is energy (or work) per second.

Where is the energy from the engine going apart from into kinetic energy, KE?
 
some would have to be going into potential energy right? there's no friction or air resistance so nothing else could be taking energy
 
well I got to the correct answer I decided to measure the problem after the car had traveled 1 meter, used kinematics to find the final speed then put

KE/(KE+PE) and it worked out because the masses canceled out and i got .538 which is correct will the method always work out if there is no friction or any other forces to worry about. It seems like this isn't the correct way to do it.
 
physstudent1 said:
well I got to the correct answer I decided to measure the problem after the car had traveled 1 meter, used kinematics to find the final speed then put KE/(KE+PE)

That's correct, if you ignore friction conservation of energy is always correct - and is often the simplest way to do it.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
1K
Replies
3
Views
1K
Replies
15
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 32 ·
2
Replies
32
Views
3K
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K