4. Find an equation of motion for the following rotational mechanical system and find its transfer function, H(s)=(s)/T(s). J=1,k1=kz=1,b1=bz=1 (fort a) What are the damping constant and natural frequency of vibration of the system? What is the form of the unit step response of the system? (Note: just write the form) What is the frequency of vibration of the unit step response? Please sketeh its unit step response. What is the steady state value of the unit step response? What is the form of the angular velocity of the system when the external torque is a unit step