vikas askiitian expert
Last Activity: 14 Years ago
let the length of thread over the table is L1 & below the table is L2 ...
L1+L2 = L ...........1
tension in upper part as wel as lower part will be same because the thread is massless , let it beT ....
mass m is circulating with angular velocity W1 so
T = mW12L1 ........2 (L1 is the radius of circle)
(tension in the thread provides necessary centripital force )
now ,
another mass is moving in conical pendulam , let it is making an angle @ with verticle then
Tcos@ = mg ..........3
Tsin@ = mW22 R ........4 (R is the radius of circular path)
R = L2sin@
putting value of R in eq4 we get
T = mW22L2 ........5
equating 2 & 5
L1/L2 = W22/W12 ans (a)
1/W12 + 1/W22 = mL1/T + mL2/T (from eq 2 & 5 )
=m(L1+L2)/T
=mL/T (L1+L2=L)
=Lcos@/g ( substituting T from eq 3)
cos@ = max =1 so
1/W12+1/W22 < L/g ans (d )
thus option a,c,d are correct