## Yahoo! 2 years ago The system Shown ( the spring is without tension) travels towards the wall and has an elastic collision . The maximum Compression of the spring is ?

1. Yahoo!

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@experimentX @siddhantsharan

3. experimentX

1/2 mv^2 = 1/2 kx^2

4. Vincent-Lyon.Fr

Why did you close this question?

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@Vincent-Lyon.Fr

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@shubhamsrg

7. shubhamsrg

for maximum compression..whole kinetic energy is transferred to spring energy...that helps ?

8. shubhamsrg

and in such case,,effective mass = m1 m2 / (m1 + m2) am i helping ?

9. shubhamsrg

i mean are you getting ?

10. Yahoo!

wat is effective mass

11. shubhamsrg

2 masses are connected to a spring on 2 ends..say m1 and m2.. then the effective mass is m1 m2/ (m1 + m2)

12. Yahoo!

ok..)

13. Yahoo!

Wait....I mean....I did nt get...wat is effective mass shuld nt it be m1 + m2

14. shubhamsrg

effective mass or can be also called reduced mass of the system.. never heard of it ?

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No..)

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So.... 1/2 k x^2 = 1/2 effective mass * v^2

17. Yahoo!

right?

18. shubhamsrg

seems right..

19. shubhamsrg

well reduced mass is no big deal..has a simple derivation.. you wanna know ?

20. shubhamsrg

there isnt much need for the derivation for you to know since you're JEE aspirant..but still i can tell if you want..

21. Yahoo!

Yes..i am interested in it

22. shubhamsrg

kk..newton's 3rd law states that F1 = -F2 right ? both taken in vector form.. F1 will be one acting on 1st body,,F2 on second..

23. Yahoo!

ok...

24. shubhamsrg

all expressions are in vector form below : m1 a1 = - m2 a2 =>a1 = (-m2/m1) a2 now relative acceleration between the bodies a = a2 - a1 = a2 (1 + m2/m1) = m2 a2 ( m1 + m2)/(m1 m2) following ?

25. shubhamsrg

??

26. shubhamsrg

tell me if not getting anything ? we are not done yet with the thing..

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28. Yahoo!

Tell me a Scenario where we will use Effective Mass

29. shubhamsrg

right here!!

30. Yahoo!

Another..Eg

31. shubhamsrg

now..m1m2 / (m1+ m2) = M (reduced or effective mass) so we have F2/M = a or F2 = Ma so what do you conclude ?

32. shubhamsrg

see,,any 2 body system can be converted to 1 body system with this effective mass... force acting between them will also act between this one body system..

33. Yahoo!

Nw..i get it...)...thxx....)

34. shubhamsrg

you sure?

35. Yahoo!

Yes.

36. shubhamsrg

hmm,,whats the conclusion you can draw then?