How Much Work Does a Plane's Engine Perform to Reach 3200m at 65m/s?

Click For Summary

Homework Help Overview

The problem involves a 1500 kg plane that ascends to an elevation of 3200 m while traveling at a speed of 65 m/s. The original poster seeks to determine the minimum work performed by the plane's engine during this ascent, disregarding air resistance.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply kinematic equations but expresses uncertainty about their relevance. They note initial conditions and question what might be missing in their understanding.
  • Some participants suggest considering conservation of energy as a relevant principle, prompting further inquiry about the relationship between kinetic and potential energy.
  • Questions arise regarding the expected relationship between changes in energy and whether they should sum to zero.

Discussion Status

The discussion is exploring the application of conservation of energy principles. Some participants have identified the relationship between kinetic and potential energy, while others are questioning the assumptions about energy conservation in this context. There is no explicit consensus on the interpretation of energy changes.

Contextual Notes

The original poster is working under the constraints of a homework assignment and is seeking clarification on the application of physical principles without complete solutions being provided.

Some_Thing
Messages
5
Reaction score
0

Homework Statement



A 1500 kg plane, initially at rest, leaves an airfield and a short time later it is at an elevation of 3200 m traveling at 65 m/s. What is the minimum work done by the plane's engine in this time? (Ignore air resistance)


Homework Equations



W=Fd, F=ma, and most certainly some other ones.


The Attempt at a Solution



This is what I understand from the question:

Vox = 0 m/s

Voy = 0 m/s

dy = 3200 m

m = 1500 kg

I assume that at 3200m, the plane starts to fly only horizontally, so "65 m/s" would be Vfx.


The problem is that this seems insufficient for any of the kinematics formulas, and I don't see how I could use it in different areas (like dynamics).


What am I missing here? Can someone please give me a push in the right direction?

Any help is greatly appreciated,

Thanks.
 
Physics news on Phys.org
Kinematic equations won't do you any good here. Can you tell me which quantity is conserved in this system?
 
Cyosis said:
Kinematic equations won't do you any good here. Can you tell me which quantity is conserved in this system?

Ah, I see, its one of those conservation of energy questions, isn't it?

Change in Ek + Change in Ep = the correct answer (5.0 x 10^7)

Thanks!


One thing bugs me though. Shouldn't these two add up to 0?
 
Some_Thing said:
Ah, I see, its one of those conservation of energy questions, isn't it?

Change in Ek + Change in Ep = the correct answer (5.0 x 10^7)

Thanks!


One thing bugs me though. Shouldn't these two add up to 0?

Why would they add up to zero?

There is no potential energy on the ground. The change in kinetic energy on the ground is converted to potential energy at 3200m in the air and kinetic energy to make it travel at 65m/s
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 12 ·
Replies
12
Views
10K
Replies
21
Views
4K
Replies
1
Views
2K
Replies
3
Views
2K