How Is the Weight of a Bird Calculated When It Sits on a Kite?

  • Thread starter Thread starter justinh8
  • Start date Start date
  • Tags Tags
    Bird Weight
Click For Summary

Homework Help Overview

The problem involves a kite being flown at two different angles due to the addition of a bird sitting on it. The initial angle is 50 degrees with a tension of 15 Newtons, and the new angle is 30 degrees after the bird lands. The task is to calculate the weight of the bird while considering the forces acting on the kite and the wind's influence.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the forces acting on the kite in both scenarios, including tension, wind force, and weight. Some attempt to calculate the weight of the bird by analyzing the differences in forces and angles, while others question the assumptions about the tension remaining constant.

Discussion Status

The discussion is ongoing, with various methods being proposed to analyze the problem. Some participants express uncertainty about their calculations and seek clarification on the relationships between the forces. There is recognition that the tension may change with the addition of the bird, leading to different interpretations of the problem setup.

Contextual Notes

Participants note that the force exerted by the wind remains constant in both scenarios, which influences their calculations. There is also mention of potential errors in assuming the tension remains at 15 Newtons after the bird lands, indicating a need for careful consideration of the forces involved.

  • #31
I say decelerated, because, initially, the kite has a tension and in equilibrium, but when the weight exerts a force on the kite, the kite moves with some force that will accelerate the kite to move down y axis, yet somehow the kite stops. I suspect that there then would exist a deceleration sometime between the weight exerted by the bird on the kite and when the new equilibrium position is reached. I think there is a change in acceleration with respect to time in this sense, because the wind force is such a weird thing to deal with where its force increases with increasing velocity. So, I mean, what do you think about the idea of the wind force in this situation?

Also, I want to note that the components of the tension do in fact change with a change in angle. As the angle gets shorter, the tension in the y direction decreases and that's also partially why this is a strange situation to me.
 
Physics news on Phys.org
  • #32
Rayquesto said:
I say decelerated, because, initially, the kite has a tension and in equilibrium, but when the weight exerts a force on the kite, the kite moves with some force that will accelerate the kite to move down y axis, yet somehow the kite stops. I suspect that there then would exist a deceleration sometime between the weight exerted by the bird on the kite and when the new equilibrium position is reached. I think there is a change in acceleration with respect to time in this sense, because the wind force is such a weird thing to deal with where its force increases with increasing velocity. So, I mean, what do you think about the idea of the wind force in this situation?

Also, I want to note that the components of the tension do in fact change with a change in angle. As the angle gets shorter, the tension in the y direction decreases and that's also partially why this is a strange situation to me.

What you say about a real kite in a real wind with a real string and a real bird is all correct. However an important part of the original post/question was:
"Assume that the force exerted by the wind on the kite alone is exactly the same as the force exerted by the wind on the kite and bird together"

This immediately made the problem a simplified, idealised situation, so real world logic is no longer that important.

As you obviously realize, the behaviour of wind, with the kite tipping at different angles is extremely complex - that is why, in this case, a greatly simplified situation is to be assumed.

Many problems we are presented with in school/college physics are simplified/idealised presentations of an every day occurrence, and we have to be ready to go with that.

When was the last time you had to deal with a satellite in elliptical orbit, and allow for added air resistance at the points where it is nearer the Earth?
We mostly idealise to perfectly circular orbit around a perfectly spherical Earth of uniform density.
We mostly assume air resistance is insignificant [ignored], or constant regardless of speed.
Surfaces are magically frictionless etc. etc.
Even when launching a rocket that achieves enormous speed, we still ignore the air resistance.

This stopped
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
9K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 24 ·
Replies
24
Views
3K
Replies
6
Views
3K
  • · Replies 35 ·
2
Replies
35
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
7
Views
7K
Replies
2
Views
2K
Replies
1
Views
3K