IIT JEE , AIEEE Forum - Physics , Mechanics

sonalisapal

a weight of 200kg wt is hung from a string which is wound over a light frictionless pulley.on the other hand a very heavy weight is hung..find the tention in the string. ANS:400 N

puneet

Well let the other mass be M where M >> 200.

Now by balancing the forces at mass of 200kg we get

T - 200g = 200a

Similarily by balancing forces at mass M we get

Mg - T = Ma

Now eliminating acceleration a we get,

T = 400Mg / ( 200 + M)

Since M >> 200, 200 can be neglected as compared to M

So, T = 400Mg/M

And thus T = 400g

pinakinab

I completely agree your answer but your unit of final answer is wrong

ROHIIT

I TOO

priya.firebolt

i think it is correct

units of g is m/s^2

units of T is kgm/s^2 which is N

joyfrancis

The correct equation of the block of weight 20Kg is

T-200=20a

(and not T-200g=200a--according to puneet sir)because it is not a mass of 200kg but a weight of 200kg and Weight=Mass*g

Similarly the second equation would be

M-T=Ma/10

on solving the two equations we get

T=400M/200+M

=400N(sinceM>>>>200)

georgek

puneet hasnt given any unit .its 400g (where g is accel due to gravity . )&taking tension as a force there shouldnt b any mistake .but i didnt get joy"s way of doing it

Ask & Discuss Questions with Community & Experts