# Which one will break ???

A mass of 1 kg is suspended by a string A . ANother string C is connected to its lower end[ See fig). if a sudden jerk is given to C , then

a) the portion AB of the string will break
b)the portion BC of the string will break
c) none of the strings will break
d)Both the portion AB and BC of the string will break.

1
Shakexpear Allll Izzz WeLL... ·

plz give ur reason also !!!! [147]

1
Shakexpear Allll Izzz WeLL... ·

answer given is (a)

but should be (b) !!!

1
JOHNCENA IS BACK ·

dude if anything will break it is AB...............

moreover question is incomplete........or i should say insufficient information is provided to decide anything :)

1
Shakexpear Allll Izzz WeLL... ·

anand.. ur answer is right and question is also complete !!!

plz give d reason ???

49
Subhomoy Bakshi ·

yeah correct....but then discuss if the force is applied not with jerk but its magnitude is increased slowly!!!

1
Shakexpear Allll Izzz WeLL... ·

hey see , wat i though was ...

when we will give a sudden jerk , then first an impulsive tension will develop in BC first , then it will go to AB .

so that impulsive tension should break the AB and it will not reach BC .

23
qwerty ·

MIT - walter lewin question [3]

1
Shakexpear Allll Izzz WeLL... ·

dunno .. it came in my test !

23
qwerty ·

if its a jerk then the lower string brks first , hence ans is b

23
qwerty ·

consider 2 cases:
1] when we are pulling the string slowly
2] when we pull it wid a jerk

in case 1 , the force F with wich we pull the string is equal to the tension of dat string , since we r pulling it slowly , i.e a = 0

so F=T

after drawing FBD , the tension in upper string comes out to be

T1=mg+T= mg +F

so as F increases , T increases .
since T1 is gr8er than T by mg at all times, it will reach its elastic limit first and will brk

in case 2 , when we pull it wid a jerk , the impulse is gr8er than the elastic limit of the lower string . And b4 it could transfer this impulse to the upper string , it brks .

this is the explanation that is coming to my mind right now [3]

1
Shakexpear Allll Izzz WeLL... ·

I agree with qwerty !!

1
Aman kumar singh ·

My answer is b option.And the portion BC will break.

1
Aniket Varshney ·

BC will break bcoz time would be less on BC and impulsive force would be large