Calculating Potential Energy Changes in a Roller Coaster System

AI Thread Summary
The discussion revolves around calculating the gravitational potential energy (GPE) changes of an 800 kg roller-coaster car moving from point A to point B. The initial calculations presented are incorrect, particularly in the use of the angle and the height change. The correct height change is determined to be 9.6 meters, which should be used in the GPE formula. Participants emphasize the importance of correctly interpreting the angle and height in the calculations to arrive at the right potential energy values. Accurate application of these concepts is crucial for determining the energy changes in the roller coaster system.
Tmtamrak
Messages
5
Reaction score
0
A 800 kg roller-coaster car is initially at the top of a rise, at point A. It then moves 135 ft, at an angle of 40.0° below the horizontal, to a lower point B.
(a) Choose the car at point B to be the zero configuration for gravitational potential energy of the roller coaster-Earth system. Find the potential energy of the system when the car is at points A and B, and the change in potential energy as the coaster moves.



GPE = mgy cos theta


This is my attempt to solve, however I keep getting that my answer is wrong.
(800kg)(9.8)(41.15m)x cos 40 =247,138.19J

Can someone please let me know what is incorrect in my process?
 
Physics news on Phys.org
Tmtamrak said:
A 800 kg roller-coaster car is initially at the top of a rise, at point A. It then moves 135 ft, at an angle of 40.0° below the horizontal, to a lower point B.
(a) Choose the car at point B to be the zero configuration for gravitational potential energy of the roller coaster-Earth system. Find the potential energy of the system when the car is at points A and B, and the change in potential energy as the coaster moves.



GPE = mgy cos theta


This is my attempt to solve, however I keep getting that my answer is wrong.
(800kg)(9.8)(41.15m)x cos 40 =247,138.19J

Can someone please let me know what is incorrect in my process?

Suppose that the angle is zero degrees below the horizontal. What would be the height change?

Now put zero into your formula instead of 40.

Why is it different? Just becos.
 
The height changes by 9.6m...

If I do (800kg)(9.8)(41.15m) = 322,616J
.. but that is not the correct answer either.
 
Tmtamrak said:
The height changes by 9.6m...

If I do (800kg)(9.8)(41.15m) = 322,616J
.. but that is not the correct answer either.

0 degrees from horizontal is horizontal...
 
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »

Similar threads

Understanding the Work-Energy Theorem: Solving the Roller Coaster Problem
Replies
8
Views
3K
What is considered the "System" here? (conservation of energy problem)
Replies
20
Views
2K
Conservation of Energy for a roller coaster
Replies
15
Views
5K
Energy Equation for a Roller Coaster on a Full Circular Loop
Replies
2
Views
2K
Electric Potential Energy of Point Charge Systems
Replies
2
Views
870
How Is the Force on a Child in a Roller Coaster Calculated?
Replies
3
Views
7K
Is potential energy defined only for internal conservative forces?
Replies
15
Views
1K
Potential Energy of a roller coaster cart
Replies
1
Views
3K
Friction between roller coaster and track
Replies
15
Views
7K
Change in potential energy on a roller coaster drop (frictionless)
Replies
2
Views
3K

Hot Threads

Recent Insights

Back
Top