A block of mass `m` is attached to two unstretched springs of spring constant `k`, each as shown. The block is displaced towards right through a distance `x` and is released The speed of the block as it passes through the mean position will be

Options

A. `xsqrt((m)/(2k))`
B. `xsqrt((2k)/(m))`
C. `xsqrt((m)/(k))`
D. `x(2k)/(m)`

Answer

B

Explanation

(b)
Total QE of spring =Total KE of block
`(1)/(2)kx^(2)+(1)/(2)kx^(2)=(1)/(2)mv^(2)`
`kx^(2)=(1)/(2)mv^(2) rArr v=sqrt((2k)/(m))x`
`W_(f)`=loss in mechanical energy
`mu mgd=mgd rArr d=5 m`.