The length of a rectangle is the same as the length of each side of a square. The length of the rectangle is 4cm more than 3 times the width of the rectangle.
The area of the square is 66cm squared more than the area of a rectangle. Find the length and the width of the rectangle.

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).