• I
Feynman Lectures 15-4 Transformation of time first para
http://www.feynmanlectures.caltech.edu/I_15.html
How is it possible that the moving clock slows down and also shows more time elapsed to the man outside?

Last edited:

PeterDonis
Mentor
2020 Award
@Jazzyrohan I don't know where all the HTML cruft in the first paragraph your post is coming form, but it makes it unreadable.

How is it possible that the moving clock slows down and also shows more time elapsed to the man outside?

It shows less time elapsed to the man outside. That is what "running slow" means.

russ_watters
Ibix
2020 Award
All I see is a pair of broken image tags. You are aware that the Feynman lectures are available online? What diagram/equation/section/whatever are you talking about?

All I see is a pair of broken image tags. You are aware that the Feynman lectures are available online? What diagram/equation/section/whatever are you talking about?
Please do take a look now.

@Jazzyrohan I don't know where all the HTML cruft in the first paragraph your post is coming form, but it makes it unreadable.

It shows less time elapsed to the man outside. That is what "running slow" means.
Please do take a look now.

Ibix
2020 Award
Please do take a look now.
That agrees with what Peter said. The "outside" observer's watch measures more ticks (by a factor of ##1/\sqrt{1-u^2tc^2}##) because the "moving" observer's watch ticks slow.

PeterDonis
Mentor
2020 Award
Please do take a look now.

The wording is confusing. The last sentence should read: "That is, when the clock in the spaceship records 1 second elapsed, as seen by the man in the ship, the clock carried by the man outside shows ##1 / \sqrt{1 - u^2 / c^2}## second to the man outside."

The wording is confusing. The last sentence should read: "That is, when the clock in the spaceship records 1 second elapsed, as seen by the man in the ship, the clock carried by the man outside shows ##1 / \sqrt{1 - u^2 / c^2}## second to the man outside."
Why is it that every material I am reading on Special Relativity is consisting of confusing wordings? I am stuck on understanding time dilation due to this.I am thinking of reading Special Relativity by AP French now.Will that be a good choice?

PeterDonis
Mentor
2020 Award
Why is it that every material I am reading on Special Relativity is consisting of confusing wordings?

What material have you read? The Feynman Lectures are generally good, but that's not to say they're perfect, and they are not specialized for teaching SR.

I am thinking of reading Special Relativity by AP French now.Will that be a good choice?

Unfortunately I have not read that book so I can't comment on it. My usual suggestion is Taylor & Wheeler's Spacetime Physics.

French's book is very good but old-fashioned. He discusses experimental evidence at length and covers a lot of ground (including Terrell rotation if I remember correctly). Old-fashioned because he uses relativistic mass and he doesn't spend much time on the geometric view of spacetime (four-vectors are covered but only briefly toward the end I think).

I second Taylor & Wheeler as an introduction.