Find the rate at which the spring is oscillating at t = 9 s. Round your answer to four decimal places.

Question

A mass on a spring bounces up and down in simple harmonic motion, modeled by the function   where   is measured in centimeters and   is measured in seconds. Find the rate at which the spring is oscillating at   s.  Round your answer to four decimal places.

_____ cm/s

Been struggling on this one, my answer is always close, but I seem to be messing up somewhere and could use some help. 

Answer 1

Solution:

The equation of distance S(t) as a function of time t is given as

S(t) = 2 cos t , To find the speed take the derivative of the S(t) equation wrt to t

dS(t) / dt =V(t) = - 2 sin t substitute for t = 9 s, V(t) = -2 sin 9 ( rad) = -2 ( 0.412) = -0.824 cm/s