How do I answer this and can you explain it to me​

Perry observes the opposite parallel walls of a room in how many lines do the plains containing the walls intersect

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).

Which angle of rotation is an angle of rotational symmetry for all figures?