There is a disc of mass M and radius R. A pont charge +Q and of mass m is fixed at the centre of the disc. The disc is held on a fixed horizontal rough suface . Another point charged +q is fixed on the surface such that disance between +q and +Q is (4R)/3. Now the disc is set free. If the disc does not loose contact with the ground at the same intent the relation must hold is Mgt eta m. Find eta. (Use (27Qq)/(256pi epsilon_(0)R^(2))=3mg)

There is a disc of mass M and radius R. A pont charge +Q and of mass m

1.	There is a disc of mass M and radius R. A pont charge +Q and of mass m is fixed at the centre of the disc. The disc is held on a fixed horizontal rough suface . Another point charged +q is fixed on the surface such that disance between +q and +Q is (4R)/3. Now the disc is set free. If the disc does not loose contact with the ground at the same intent the relation must hold is Mgt eta m. Find eta. (Use (27Qq)/(256pi epsilon_(0)R^(2))=3mg)
Answer» Solution :`(M+m)g gt F_(E)sintheta` `gt( 27Qq)/(256piepsilon_(0)R^(2))` `(M+m)g gt 3MG` `Mgt2mrarreta=2`

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