Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Does space have a physical role in the jerk of acceleration?

  1. Apr 9, 2013 #1
    Does space have a physical role in the "jerk" of acceleration?

    This "jerk" that the great Einstein talks about in his book is really confusing me. Without space, there seems not to be a medium through which matter can move, thusing allow it (matter) to make sense of "force."

    I'll use one golden retriever in this example. Her name is Isabelle.

    Isabelle is suspended in deep, deep space. Suddenly she turns on her rocket booster. She accelerates. Okay, now she feels this "jerk" Einstein talks about. From my understanding, this is a "force." Gravity (force of nature) is equivalent to acceleration. Okay, but what role does space (maybe spacetime) have in the golden retriever's feeling of this jerk?

    The easy answer is: without space, nothing exists. I accept that. I'm just wondering if space has some unacknowledged role in the "jerk" matter feels when it is accelerated or decelerated. Or does space play no physical role in this?
    Last edited: Apr 9, 2013
  2. jcsd
  3. Apr 9, 2013 #2


    User Avatar
    Science Advisor
    Gold Member

    The answers haven't changed since the last time you asked this question:
    My answer was (and still is):
    And you said:
    What happened?
  4. Apr 9, 2013 #3
    Time keeps everything from happening at once;
    space keeps everything from happening at the same location.

    Things would be really confusing otherwise!
  5. Apr 9, 2013 #4


    Staff: Mentor

    Gravity is equivalent to coordinate acceleration. The acceleration due to the force from the rocket is a proper acceleration. There is no equivalence between it and gravity.
  6. Apr 9, 2013 #5

    Naty1 brings up a good point that you did not. This "jerking" from acceleration is important, and I'm trying to look at it from different angles. In yesterday's post, I said nothing about space's role in this, so just because my question involves golden retrievers, you needn't reduce it to being a copy of yesterday's question. There's a lot to mine in discussing acceleration.
  7. Apr 9, 2013 #6


    User Avatar
    Science Advisor
    Gold Member

    I actually thought Naty1 was trying to be funny (in frustration).

    You're looking for space to be a medium so that matter can make sense of force and motion?

    It is very difficult to figure out what you are concerned about. You are asking some very basic questions that have nothing to do with relativity. They are the kind of issues that you should have learned about from studying general physics long before you take on relativity.
  8. Apr 9, 2013 #7


    Staff: Mentor

    Didn't John Wheeler once put it: "time keeps everything from happening at once; space keeps everything from happening to me."
  9. Apr 9, 2013 #8

    Vanadium 50

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2017 Award

    As mentioned before, it is neither unnecessary nor desirable to start multiple threads on the same topic.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook