Rick bought 3 shirts for $18 each, 2 pair of socks for $3.99 a pair, and a pair of leggins for $45.00. The sales tax rate is 8.5%. How much did he pay?

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).