In forced oscillations displacement equation is `x(t) = A cos(omega_(d) t + theta)` then amplitude .A. vary with forced angular frequency `omega_(d)` and natural angular frequency `.omega.` as (b = damping constant)

Options

A. `(F)/(m omega^(2))`
B. `(F)/({m^(2)(omega^(2)-omega_(d)^(2))^(2) + omega_(d)^(2) b^(2)}^(1//2))`
C. `(F)/({m^(2)(omega_(d)^(2)b^(2))-(omega^(2)-omega_(d)^(2))}^(1//2))`
D. `(F)/({m(omega_(d)^(2)b^(2)) + (omega^(2)-omega_(d)^(2))}^(1//2))`

Answer

B