ElectrostaticsHard
Question
Two smooth spherical non conducting shells each of radius R having uniformly distributed charge Q & - Q on their surfaces are released on a smooth non-conducting surface when the distance between their centres is 10 R. The mass of A is m and that of B is 2 m. The speed of A just before A and B collide is: [Neglect gravitational interaction]
Options
A.
B.
C.
D.
Solution
By conservation of momentum
m VA = 2m VB . ∴
= 
Also,
= 2 (where KA & KB are K.E. of A & B respectively)
from conservation of mechanical energy principle :
Ui + Ki = Uf + Kf or
+ = − 
+ KA + KB
∴ KA + KB =
+ 
= 
KA +
= 
KA = 
KA =
or
mvA2 = 
∴ VA = 
m VA = 2m VB . ∴
= Also,
= 2 (where KA & KB are K.E. of A & B respectively)from conservation of mechanical energy principle :
Ui + Ki = Uf + Kf or
+ = − + KA + KB∴ KA + KB =
+ = KA +
= KA = KA =
or
mvA2 = ∴ VA = Create a free account to view solution
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