4. A mass m is on a frictionless table and is attached to the wall by a massless spring (spring constant k). The air friction on the block is f=-2Bmv. During an earthquake, the wall moves left and right as y(t) = Bcos w t. y(t)=Bcos w t m x(t)=? (a) Show that the eqn. of motion for m is x + 2Bx + wax = f coswt with Wo = m Express fin terms of B and wo. (3 pts) (b) Derive the amplitude of the m oscillation. (5 pts) (c) What is the amplitude at the resonance frequency w = wo? (2 pts)