Need help with a Work and Energy problem

Click For Summary

Homework Help Overview

The discussion revolves around a work and energy problem involving a car traveling up an incline. The car's weight, speed, incline angle, and opposing frictional force are provided, with specific calculations requested regarding potential energy gain, work done against friction, and engine power.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between distance traveled and potential energy gain, with some noting the car's speed provides a means to determine distance over time. Questions arise regarding the interpretation of "gain in potential energy per second" and its relation to vertical height versus distance along the slope.

Discussion Status

The conversation is ongoing, with participants providing insights and clarifications about the problem's parameters. There is a focus on understanding the definitions and implications of the terms used in the problem, particularly regarding potential energy and the units of measurement.

Contextual Notes

Participants express uncertainty about the vertical distance traveled by the car and how it relates to the calculations required. There is an acknowledgment of the need for clarity on the definitions of potential energy in the context of the incline.

suzukits
Messages
8
Reaction score
0

Homework Statement


A car of weight 7000N travels at a steady speed of 8m/s up a steady incline at 15degrees above the horizontal. The car's motion is opposed by a constant frictional force of 500N.

Homework Equations


Calculate:
a) the gain in p.e per second
b) the work done per second against friction
c) the car's engine power.

The Attempt at a Solution


I keep getting the wrong answer. It would be easier if I knew the distance traveled by the car but I don't know any suitable formula.

Help is appreciated!
 
Physics news on Phys.org
Welcome to these forums!

The car travels 8 m along the incline every second (given).
 
In a way you do know the distance because the question is asking for the gain in PE per second and you know how far the car travels in 1 second (8m/s)
Hope this gets you into the question
 
Does that mean that the answer should be in Watts? Since its J/s?
 
Yes... all the answers will be joules per second...ie watts
 
but what exactly does "gain in potential energy per second" mean?
is it just 8? since that's the velocity
 
PE is due to change in VERTICAL height ...mgh...?
The 8m/s is along the slope...not vertical
 

Similar threads

  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
2
Views
2K
Replies
5
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 5 ·
Replies
5
Views
15K
  • · Replies 3 ·
Replies
3
Views
6K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
8
Views
3K