TargetIIT

In a simple fixed pulley system, two unequal masses m[ss]1[/ss] and m[ss]2[/ss] are connected by a light string passing over a light fixed pulley.

the larger mass is stopped for a momment 2 secs after the system is set into motion. Find the time elapsed before the string is tight again...

m[ss]1[/ss]=300g
m[ss][ss]2[/ss][/ss]=600g


now the words a momment or an instant are tricky.....by these how much time is meant other wise the problem is not a problem!!

what about this???

i just want to know what is the meaing of the phrase the larger mass is stopped [b]for a momment..[/b].......how much time is that supposed to mean???help please!![2][2]

[image]43997609.jpg[/image]


now if this describes the situation described in the sum then, what i ask is what is the value of dt???

if image is too unclear use magnifier....

yea red lines signify the direction of velocity and black lines signify the direction of acceleration!!  and i cannot edit posts!![2][2]

some one clarify!![2][2]

.66 seconds ???

LOL ............ how did you know that????????????

i solved this

but how the hell were we supposed to know this???

SIMPLY SUPPOSE AT t=2 sec the large block starts moving from rest and small block has velocity which it gained in first 2 seconds
[image]44016990.jpg[/image]
after 2 seconds they become free from each other for some time
for finding time assume length of string is constant and equate distance travelled by 300 kg in upward = distace travelled by 600 kg in downward from rest.

How do u suppose that at t=2 sec, the larger block starts to move?

I'm getting the ans as [im]http://codecogs.izyba.com/gif.latex?%5Cfrac%7B3Mv%7D%7B2g%28m+M%29%7D[/im] where [im]http://codecogs.izyba.com/gif.latex?v%3D%5Cfrac%7B4g%7D%7B3%7D[/im] & M is the larger block.

at t=2sec the large block is STOPPED FOR A MOMENT, NOT PERMANENTLY STOPPED..
u assumed that the block is permanently stopped so u are getting twice the answer from my answer....

for a moment means the velocity of that mass will be zero.
Then it gain starts accelerating

I have assumed it to be at rest only for a moment harsh - the assumption that u are talking would give an entirely different ans.

I did the way virang is thinking on.

I THINK YOUR VELOCITY IS WRONG
CHECK UR VELOCITY
I GET IT AS 20/3 BUT U GET AS 40/3