its height is given by -An object attached to a spring bounces up and down - calculus

Question

An object attached to a spring bounces up and down. Its height is given by

h(t) = 60 − 20cos(0.2t + 0.4)

where h is in inches and t is in seconds. What is the object's velocity at the instant t = 5 seconds? Be accurate to two decimal places and include correct units.

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Answer 1

v(t) = h'(t) = 4sin(0.2t + 4); v(5) = 4sin(1.4) = 3.94 inch/sec