Notices

View Poll Results: What is answer the following question?

Voters
1. You may not vote on this poll
  • Option A

    0 0%
  • Option B

    0 0%
  • Option C

    1 100.00%
  • Option D

    0 0%
Results 1 to 10 of 10

Thread: Help in speed problem please

  1. #1 Help in speed problem please 
    Genius Idiot Rajnish Kaushik's Avatar
    Join Date
    Jan 2014
    Posts
    168
    hello i need help in solving this
    Q)If the speed of a vehicle increases by 2 m/s,its kinetic energy is doubled,then original speed of the vehicle is
    a)(sqrt of 2 )+1 m/s

    b)2(sqrt of 2 -1)m/s
    c)2(sqrt of 2 + 1 )m/s
    d)sqrt of 2 (sqrt of 2 + 1)m/s
    sqrt is square root of
    please help me out
    Thnx in advance


    Reply With Quote  
     

  2.  
     

  3. #2  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    11,697
    What have you got so far?
    We don't answer homework questions, but we'll help YOU arrive at the answers.


    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  4. #3  
    Genius Idiot Rajnish Kaushik's Avatar
    Join Date
    Jan 2014
    Posts
    168
    I found the answer as 2(sqrt of 2 + 1 )m/s i just want you to cross check it
    Reply With Quote  
     

  5. #4  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    11,697
    Quote Originally Posted by Rajnish Kaushik View Post
    I found the answer as 2(sqrt of 2 + 1 )m/s
    Not useful.
    HOW did you arrive at that answer?
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  6. #5  
    Genius Idiot Rajnish Kaushik's Avatar
    Join Date
    Jan 2014
    Posts
    168
    i just used the identity 1/2*m*(v+2)^2 = 1/2*m*v^2 * 2
    Reply With Quote  
     

  7. #6  
    Genius Idiot Rajnish Kaushik's Avatar
    Join Date
    Jan 2014
    Posts
    168
    1/2*m*(v+2)^2 = 1/2*m*v^2 * 2 ie KE=PE
    Reply With Quote  
     

  8. #7  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    11,697
    And did you check it?
    E.g.:
    2(sqrt of 2 + 1 )m/s = (2(1.414+1) = 4.828 m/ s,
    Square that = 23.3.

    New value = 6.828 (i.e. adding 2 m/ sec).
    6.8282 = 46.6.

    46.6/23.3 = 2.

    Confirmed.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  9. #8  
    Genius Idiot Rajnish Kaushik's Avatar
    Join Date
    Jan 2014
    Posts
    168
    Quote Originally Posted by Dywyddyr View Post
    And did you check it?
    E.g.:
    2(sqrt of 2 + 1 )m/s = (2(1.414+1) = 4.828 m/ s,
    Square that = 23.3.

    New value = 6.828 (i.e. adding 2 m/ sec).
    6.8282 = 46.6.

    46.6/23.3 = 2.

    Confirmed.
    So i was right yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee eeeeeeeeeeeeeeeee
    Reply With Quote  
     

  10. #9  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    11,697
    I've always found that plugging in the numbers and actually calculating them helps.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  11. #10  
    Genius Idiot Rajnish Kaushik's Avatar
    Join Date
    Jan 2014
    Posts
    168
    Quote Originally Posted by Dywyddyr View Post
    I've always found that plugging in the numbers and actually calculating them helps.
    Thnx for advice please cart your vote above
    Reply With Quote  
     

Similar Threads

  1. Replies: 11
    Last Post: November 18th, 2011, 03:59 AM
  2. Problem with the constancy of the speed of light.
    By astray in forum General Discussion
    Replies: 11
    Last Post: November 18th, 2011, 03:59 AM
  3. Excel speed problem
    By newnothing in forum Computer Science
    Replies: 0
    Last Post: March 1st, 2009, 01:45 AM
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
  •