A graphing calculator is recommended. An elastic band is hung on a hook and a mass is hung on the lower end of the band. When the mass is pulled downward and then released, it vibrates vertically. The equation of motion is s(t) 2 cos(t) +7 sin(t), t 0, where s is measured in centimeters and t in seconds. (Take the positive direction to be downward.) (a) Find the velocity and acceleration at time t. v(t) = = a(t) = (b) Graph the velocity and acceleration functions. y 6-a 2 -2 -t KI 3/ 2 2 6 2 -6 y a VA 3 52 t