A block P of mass m is placed on horizontal frictionless plane. A second block of same mass m is placed on it and is connected to a spring of spring constant k, the two blocks are pulled by distance A. Block Q oscillates without slipping. What is the maximum value of frictional force between the two blocks.

Options

A. zero
B. K
C. `(KA)/(2)`
D. `mug`

Answer

C

Explanation

Angular frequency of system
`omega=sqrt((K)/(m+m))=sqrt((K)/(2m))`
maximum acceleration `a_(max)=omega^2A`
Frictional force between `P` and `Q`
`=`force exerted on lower block
`=momega^2A=m((K)/(2m))A=(KA)/(2)`