What are the equations for finding ball position in relativity?

  • Thread starter Thread starter motherlovebone
  • Start date Start date
  • Tags Tags
    Relativity
Click For Summary

Homework Help Overview

The discussion revolves around a problem in the context of relativity, specifically involving the motion of a ball thrown by a passenger in a moving convertible. The original poster seeks to find equations that describe the ball's position in relation to both the passenger and an observer on the road.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the use of kinematic equations and transformations, questioning the necessity of time and specific position values to solve the problem. There is a focus on understanding the relationship between the velocities involved and the equations provided by the teacher.

Discussion Status

The conversation reflects a lack of consensus on how to proceed without certain variables like time or specific position values. Some participants suggest that the teacher's equations could be useful, while others express confusion about their application in this context.

Contextual Notes

There is mention of the original poster's frustration with the teacher's explanations and the perceived lack of instruction on kinematic equations, which may be impacting their ability to approach the problem effectively.

motherlovebone
Messages
11
Reaction score
0
I have a teacher who is lacking in the explanation department, so I figured I could find an answer here. We are doing relativity in class, and I have a quick question on it.

The problem is, "A passenger in a convertible throws a ball up into the air. the car is going 35 m/s. The upward velocity of the ball is 8 m/s. Give the equations that specify the ball position with regards to: the passenger (prime coordinates) and an observer on the road (unprime coordinates)."

In the above problem, we are supposed to find x, y, z, x prime, y prime, and z prime. Our teacher told us that y and y prime are the same value, which I found. However, I cannot find x, x prime, z, or z prime. Any hints would be very helpful to me. The teacher said the following: x=x'+vt and x'=x-vt. However, I do not have the time, so I can't use those equations.

Please help ASAP.
 
Physics news on Phys.org
I think it would have taken you less time to determine the answer using those equations then to write the message.

Do you know the kinematic equations for motion at rest? You can use those and just substitute the equations into each other using the Gallilean transformation.
 
But I can't use those equations because all I have is the two velocities. I don't have t, don't have x or x', and I don't know which v to use.
 
So when you say your teacher is "lacking in the explanation department" what you mean is you can't be bothered to do what he suggested?
 
Or even worse, did the teacher not know how to use the equations?
 
No. I mean that I don't understand a thing he says. I went in for help on this problem after school. He threw the two equations x=x'+vt and x'=x-vt at me, told me to figure it out, and then I left.

I don't get how I'm supposed to solve this problem without having t or either x value.
 
Well it appears that all he is asking for is the actual equations so you don't really need t although its pretty easy to figure out using the kinematic equations.
 
But on the sheet, it has answer blanks for x', y', z', x, y, z. So I'm guessing he wants all the values. And we learned nothing about kinematic equations.
 

Similar threads

  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
Replies
8
Views
2K
  • · Replies 3 ·
Replies
3
Views
870
  • · Replies 38 ·
2
Replies
38
Views
4K
  • · Replies 10 ·
Replies
10
Views
2K
Replies
13
Views
5K
  • · Replies 9 ·
Replies
9
Views
1K
Replies
12
Views
1K
Replies
2
Views
1K