Notices
Results 1 to 6 of 6
Like Tree2Likes
  • 1 Post By exchemist
  • 1 Post By MagiMaster

Thread: Hitting the light speed breaks.

  1. #1 Hitting the light speed breaks. 
    Forum Freshman
    Join Date
    Feb 2014
    Posts
    8
    Let's say, over the course of a year, a space ship accelerates to light speed and consumes 100 gallons of space fuel (it's very good space fuel). It then decides to make a full stop by shooting the thrusters in reverse. Would it take the same amount of time and the same amount of gas to decelerate to zero?


    Reply With Quote  
     

  2.  
     

  3. #2  
    exchemist
    Join Date
    May 2013
    Location
    London
    Posts
    3,518
    Quote Originally Posted by hencook View Post
    Let's say, over the course of a year, a space ship accelerates to light speed and consumes 100 gallons of space fuel (it's very good space fuel). It then decides to make a full stop by shooting the thrusters in reverse. Would it take the same amount of time and the same amount of gas to decelerate to zero?
    It must be good, as it take an infinite amount of energy to accelerate any mass to c. Presumably it also takes as infinite amount of energy to decelerate from c to zero.


    hencook likes this.
    Reply With Quote  
     

  4. #3  
    Forum Cosmic Wizard
    Join Date
    Dec 2013
    Posts
    2,408
    As exchemist says it would be an infinite amount in both cases.
    But you would still be saving the infinite amount of fuel it took to accelerate that hundred gallons of space fuel you burned getting to lightspeed as you slowed down.
    Reply With Quote  
     

  5. #4  
    Forum Radioactive Isotope MagiMaster's Avatar
    Join Date
    Jul 2006
    Posts
    3,440
    If you throw out that light speed detail, then the answer is no in both cases. The spaceship will be missing 100 gallons of fuel mass when slowing down. So you'll get more acceleration for the same force and you'll need less fuel to stop.
    SpeedFreek likes this.
    Reply With Quote  
     

  6. #5  
    ▼▼ dn ʎɐʍ sıɥʇ ▼▼ RedPanda's Avatar
    Join Date
    Aug 2012
    Location
    UK
    Posts
    2,737
    If light speed was achievable, then yes - it would require the same amount of energy to decelerate as to accelerate.
    But, as MagiMaster said, the weight of the fuel would complicate things.
    If the ship refuelled before slowing down, it would take the same amount of fuel to decelerate.
    SayBigWords.com/say/3FC

    "And, behold, I come quickly;" Revelation 22:12

    "Religions are like sausages. When you know how they are made, you no longer want them."
    Reply With Quote  
     

  7. #6  
    Quagma SpeedFreek's Avatar
    Join Date
    Jan 2011
    Location
    London, UK
    Posts
    2,787
    Have a read of this webpage:

    The Relativistic Rocket
    "Ok, brain let's get things straight. You don't like me, and I don't like you, so let's do this so I can go back to killing you with beer." - Homer
    Reply With Quote  
     

Similar Threads

  1. Speed of data traveling in relation to speed of light
    By Polarbear1981 in forum Physics
    Replies: 8
    Last Post: February 21st, 2014, 04:17 AM
  2. Is it the speed of light the max speed
    By MadeinRo in forum Physics
    Replies: 17
    Last Post: August 14th, 2011, 07:00 PM
  3. speed of light
    By zach in forum Physics
    Replies: 19
    Last Post: March 6th, 2009, 01:13 PM
  4. Speed of light going up and down?
    By Obviously in forum Physics
    Replies: 6
    Last Post: October 4th, 2007, 07:26 PM
Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •