How to Solve for an Object's KE and Heat in a Differential Equations Problem?

Click For Summary
SUMMARY

The discussion focuses on solving for an object's kinetic energy (KE) and heat in a differential equations context, specifically involving forces such as air drag and gravity. The relevant equation presented is y'' + (Force due to Drag)y' + (gravity)y = 0, which is derived from Newton's second law. Participants emphasize the importance of focusing on velocity v(t) rather than height y, as kinetic energy is independent of position. The conversation highlights the need to establish the correct initial value problem to effectively model the scenario.

PREREQUISITES
  • Understanding of Newton's second law of motion
  • Familiarity with differential equations and initial value problems
  • Knowledge of kinetic energy concepts and calculations
  • Basic principles of fluid dynamics, specifically air drag
NEXT STEPS
  • Study the derivation of differential equations from Newton's laws of motion
  • Learn how to apply initial conditions to solve differential equations
  • Explore the relationship between velocity and kinetic energy in physics
  • Investigate the effects of air drag on object motion using simulation tools
USEFUL FOR

Students in physics or engineering courses, educators teaching differential equations, and anyone interested in applying mathematical modeling to physical phenomena involving forces and motion.

steven452
Messages
3
Reaction score
0

Homework Statement



We're supposed to find the object's KE and heat. Given:

Forces on Object: Air Drag + Gravity
Air Drag = .5(coefficient of drag)(1.2 kg/m3)v2A
A = cross sectional area
R = Radius of object
Object is X Km above the ground
Initial velocity = V

We are told it should be an initial value problem.

Homework Equations



Possibly y"+ (Force due to Drag)y' + (gravity)y = 0

The Attempt at a Solution



I tried plugging in the initial conditions to the equation above, but I'm stuck at that point.
 
Physics news on Phys.org
Possibly y"+ (Force due to Drag)y' + (gravity)y = 0
How did you get that equation?

Since kinetic energy has nothing to do (directly) with position, you shouldn't have to solve for y (which I'm assuming stands for the height of the object); instead, focus on v(t), and don't forget that a(t) = dv/dt
 
I just sort of assumed that's the equation we had to use, but I wasn't sure?

What initial value differential equation should I be using?
 
You should be able to derive an equation using Newton's second law and what you know about the forces acting on the object
 
I was originally going to do it entirely with Newton's laws, but I'm having a hard time seeing how Newton's equations can "convert" into DE?
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 65 ·
3
Replies
65
Views
8K
  • · Replies 8 ·
Replies
8
Views
12K
Replies
7
Views
5K
  • · Replies 1 ·
Replies
1
Views
3K