Total Mechanical Energy Problem

Click For Summary

Homework Help Overview

The problem involves a roller coaster's total mechanical energy as it moves between different heights. The scenario includes calculating potential and kinetic energy at various points, specifically at heights of 15 m, 3 m, 8 m, and 0 m, while ignoring friction.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to understand how to calculate the velocity at different points without having direct measurements, questioning the relationship between potential energy and kinetic energy. Some participants suggest that total mechanical energy is conserved and inquire about its value at the highest point.

Discussion Status

Participants are exploring the concept of conservation of mechanical energy. Some have confirmed the total mechanical energy at the highest point, while others are still trying to clarify how to find velocities at lower points. There is a productive exchange of ideas regarding potential energy calculations.

Contextual Notes

The discussion is constrained by the lack of velocity data at points B, C, and D, and the original poster expresses uncertainty about the methods to find total mechanical energy and kinetic energy without this information.

Snape1830
Messages
65
Reaction score
0
The 120 kg roller coaster just makes it to the top of hill A that is 15 m above the ground. It moves forward, picking up speed towards location B which is only 3 m above the ground. What is the total energy of the roller coaster as it passes location B, C, and D? Note: the velocity at the top of the hill is 0 m/s. The height of C= 8m and the height of D = 0 m. Ignore friction.

I know that total mechanical energy (TME) = PE + KE. However, I only have the velocity at the top of the hill and not at points B,C, and D. How do I find the velocity? I think I've done something like the Initial PE= final KE, but is that right? My teacher never told us that. Then further down on the questions it asks us to find the velocity of the roller coaster at these points, so is there a way to find TME without knowing the velocity? Do I use Work = change in kinetic energy?

Then another question asks us to find the kinetic energy at these points.

Please help I'm really stuck!
 
Last edited:
Physics news on Phys.org
Without friction, total mechanical energy is a conserved quantity. What's the total mechanical energy at location A?
 
gneill said:
Without friction, total mechanical energy is a conserved quantity. What's the total mechanical energy at location A?
PE= mgh. So PE= 17640 JOhh I get it! So 17640=TME since kientic energy is 0 J. I completely forgot about that. Thanks!
 
Snape1830 said:
PE= mgh. So PE= 17640 J


Ohh I get it! So 17640=TME since kientic energy is 0 J. I completely forgot about that. Thanks!

:smile: You're welcome.
 

Similar threads

Understanding the Work-Energy Theorem: Solving the Roller Coaster Problem
  • · Replies 8 ·
Replies
8
Views
3K
Help with an energy problem found on the Phet Website
  • · Replies 4 ·
Replies
4
Views
11K
What is considered the "System" here? (conservation of energy problem)
  • · Replies 20 ·
Replies
20
Views
3K
Mechanical Energy of two Cannonballs fired at two different angles
  • · Replies 9 ·
Replies
9
Views
2K
Test question: What is true for a mechanical impact?
  • · Replies 7 ·
Replies
7
Views
1K
Minimum safe height for a roller coaster
  • · Replies 10 ·
Replies
10
Views
6K
Question about the conservation of mechanical energy
  • · Replies 7 ·
Replies
7
Views
2K
How Do You Calculate Energy and Speed on a Roller Coaster?
  • · Replies 8 ·
Replies
8
Views
4K
Proving that the total mechanical energy is conserved with time
  • · Replies 2 ·
Replies
2
Views
2K
Conservation of Momentum Problem - Mechanical and Kinetic Energies
  • · Replies 2 ·
Replies
2
Views
1K