menu search
brightness_auto
Feel free to answer or ask any questions.
If you are new here please see how to use or FAQ.
more_vert

Three blocks A, B and C are lying on a smooth horizontal surface, as shown in the figure. A and B have equal masses, m while C has mass M. Block A is given an brutal speed v towards B due to which it collides with B perfectly inelastically. The combined mass collides with C, also perfectly inelastically $5\over6$th of the initial kinetic energy is lost in whole process. What is value of M/m ?

(1) 4 

(2) 5 

(3) 3 

(4) 2

1 Answer

more_vert
 
verified
Best answer

Ans: (1) 4

Sol: $k_i={1\over2}mv_0^2$

From linear momentum conservation

$mv_0=(2m+M)v_f$

$\implies v_f={mv_0\over2m+M}$

${k_i\over k_f}=6$

$\implies{{1\over2}mv_0^2\over{1\over2}(2m+M)\left({mv_0\over2m+M}\right)^2}=6$

$\implies{2m+M\over m}=6$

$\implies{M\over m}=4$

thumb_up_off_alt 1 like thumb_down_off_alt 0 dislike
more_vert
Wow! Nice,very satisfying
more_vert
How ki by kf is equal to 6?

Welcome to Jee Neet QnA, where you can ask questions and receive answers from other members of the community.


Join our Telegram group for live discussion.

Telegram Group

Subscribe our YouTube channel for video solutions with explanation.

YouTube Channel

Download Jee Neet QnA Books in PDF for offline learning.

Jee Neet QnA Books

1.2k questions

842 answers

384 comments

110 users

...