simple but ....

hey guys!

there is a very popular problem... but the thing is dat i for go the trick ...

two masses m1 and m2.. and a massless pulley... as usual..

theya re moving wid some acceleration..

the thing is : let m1 be stopped for an instant..

then wat are the consequences ??

like after wat time the string will be taut??

and include all other consequences that u all think can happen.............

7 Answers

11
virang1 Jhaveri ·

Which is heavier . That is important for taking decisions

1
skygirl ·

le lo naa kuchh bhee...

m2>m1

11
virang1 Jhaveri ·

If m1 is stopped the string will be taut the very next second since m1 was being pulled by m2

11
virang1 Jhaveri ·

if we consider m1>m2

Then m1 is pulling m2. Since m1 stops it stops pulling m2. m2 will be having a velocity as it was accelerated by m1 before it stopped. The velocity is upwards. Therefore the string will become taut again after v becomes v(with opposite direction.

1
Rohan Ghosh ·

for m1>m2

well just before stopping they will have their velocities equal=v

when m1 is stopped its velocity goes to zero

then the tension vanishes and regains again when distance between them = length of thread again

after stopping m1 faces g downwards with zero velocity

m2 also faces g downwards with v velocity upwards

so let the string become taut after time t

vt-(1/2)gt2=1/2gt2

In this way we can obtain the time

also if the lighter mass is stopped in the above case

we have (let t again be time of tension regain)

vt+1/2gt2+1/2gt2=0

which gives t=0 which means the string will instantly become taut

1
skygirl ·

a BIG thankyou :)

1
AARTHI ·

tx..me 2 had da same doubt

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