Velocity question

8) 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) = -15sin(t), t 2 0 where s is in cm and t is in seconds. (Note: the positive direction is downwards.) a) Find the velocity equation with units. b) Find the acceleration equation with units. c) When does the mass pass through the equilibrium position for the first time? i. What is the velocity and acceleration at that time? d) How far from its equilibrium position does the mass travel? e) When is the speed the greatest