Calculating different time frames

  • Context: Undergrad 
  • Thread starter Thread starter Dhruv007
  • Start date Start date
  • Tags Tags
    Frames Time
Click For Summary
SUMMARY

The discussion centers on calculating the speed of an object when 1 second in the observer's frame of reference equals 100 seconds in the object's frame, utilizing the time dilation formula: $$Δt = \frac{Δt_0}{\sqrt{1 - \frac{v^2}{c^2}}}$$. Participants emphasize that if the time dilation factor is 100, the object's speed approaches the speed of light (c), specifically around 0.99995c. Confusion arises regarding the interpretation of time dilation, with some asserting that the results are counterintuitive, while others clarify that high speeds are necessary for relativistic effects to manifest.

PREREQUISITES
  • Understanding of special relativity concepts, particularly time dilation.
  • Familiarity with the formula for time dilation: $$Δt = \frac{Δt_0}{\sqrt{1 - \frac{v^2}{c^2}}}$$.
  • Basic algebra skills for manipulating equations involving speed and time.
  • Knowledge of the speed of light (c) and its significance in physics.
NEXT STEPS
  • Study the implications of time dilation in various relativistic scenarios.
  • Learn how to derive and apply the Lorentz transformation equations.
  • Explore the concept of simultaneity in special relativity and its effects on measurements.
  • Investigate the differences between Newtonian mechanics and relativistic physics in terms of speed calculations.
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in the principles of special relativity and the mathematical underpinnings of time dilation.

  • #31
Dhruv007 said:
Well i think. This is enough discussion for this topic. Clearly, this question is beyond relativity. So if i have to solve it, i would have to make a new branch of physics with completely different ideas from einstein’s relativity. And i cannot creat this branch.
No. What was done was I solved for v using the time dilation equation. That IS special relativity (and a simplified version at that).To reiterate, here is time dilation solved for v. Plug in values for t and t0 and see what you get. Here t0 is the moving clock.

$$v = c \sqrt{ 1 - \frac{t_0^2}{t^2}}$$
I already worked out every step to get to v starting with the time dilation equation. The reason the speed is imaginary when you make the moving clock tick faster is because THAT IS IMPOSSIBLE in special relativity. The moving clock will always tick slower.Edit- I used delta t’s instead of just t and t’ because I like thinking in terms of elapsed intervals of time, but it doesn’t matter since the equations are linear. t, delta t, dt, doesn’t matter. Same result. Moving clocks tick slower.

Edit 2- Oh wait I see what your saying. Yes, a moving clock ticking faster is “beyond” special relativity, in the same way that an apple falling upwards is beyond general relativity (and Newton). Your scenario is simply not possible according to physics as we know it. It requires a speed that is imaginary (a number multiplied by the square root of negative one).
 
Last edited:
Physics news on Phys.org
  • #32
Anyway, setting aside the fact that your opening post was an impossible scenario (the moving clock ticking 100 times faster than your local at rest clock- again, moving clocks tick SLOWER not faster), if you flip your numbers so that your clock reads 100 seconds in the interval and the moving clock reads 1 second, you SHOULD be getting a speed very close to c, as I believe two or three people have been pointing out.

That is what time dilation is, and it is more pronounced the faster v is. Or, you can solve for v and say this: the faster v is, the greater difference between t and t’ (with the moving clock seconds t’ < t always).The algebra was worked out step by step earlier, so that should no longer be a confusion. The only issue now is that you originally stated an impossible situation (the moving clock ticking faster than your local at rest clock). And as I’ve said a few times, if you just swap your numbers you get a POSSIBLE situation, and v turns out to be the reasonable value it should be: nearly but less than the speed of light.
 
  • #33
Dhruv007 said:
there is not a very large difference b/w V* and V. But the difference in the Dilation factor is too big. This is the abnormality that i am getting.

It's not an abnormality, it's an obvious consequence of the fact that the formula for time dilation is not linear in velocity. If you think that's an "abnormality", you need to go back and review basic math.

Dhruv007 said:
Suppose time for the moving person is normal. But time for the stationary person has slowed down. Its the opposite of time dilation

We can't suppose this because it contradicts relativity, i.e., it contradicts the actual laws of physics that have been measured very precisely in thousands of experiments.

Sorcerer said:
When you do that the speed is imaginary, as I just showed.

"Imaginary" here means "meaningless". There is no such thing.

Dhruv007 said:
Clearly, this question is beyond relativity.

No, it isn't. You are just imagining a problem that does not actually exist.
 
  • #34
The OP question has been answered. Thread closed.
 

Similar threads

  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 33 ·
2
Replies
33
Views
1K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 10 ·
Replies
10
Views
870
  • · Replies 87 ·
3
Replies
87
Views
5K
  • · Replies 42 ·
2
Replies
42
Views
4K
  • · Replies 18 ·
Replies
18
Views
2K
  • · Replies 63 ·
3
Replies
63
Views
6K
  • · Replies 26 ·
Replies
26
Views
2K
  • · Replies 35 ·
2
Replies
35
Views
2K