Question

a rod of negligible mass having length l=2m is pivoted at its centre and two masses of m1=6 kg and m2=3 kg are hung from the ends. find tension in the supports to the blocks of mass 3 kg and 6kg

Answer 1

Explanation:

REF.Image

FBD of the blocks and pivot - system :-

From equilibrium,

T1=m1g & T2=m2g⇒T1=30N & T2=60N

The tension provide a torque about O.

Z1=T2r−T1r=(60−30)×1=30N−m

also, due to rod, an additional couple appear as,

Z2=2×2r×2m3g=2m3gr=23×10×1=15N−m

∴ Net torque, Znet=Z1+Z2=45N−m

and moment of inertia about 0,

I0=12m3l2+m1