A mass weighing 32 pounds stretches a spring 2 feet.
(a) Determine the amplitude and period of motion if the mass is initially released from a point 1 foot above the equilibrium position with an upward velocity of 6 ft/s.
(b) How many complete cycles will the mass have completed at the end of 4 seconds?
Answer:

Period =
seconds
8 cycles
Explanation:
A mass weighing 32 pounds stretches a spring 2 feet;
it implies that the mass (m) = 
m= 
= 1 slug
Also from Hooke's Law
2 k = 32
k = 
k = 16 lb/ft
Using the function:

(because of the initial position being above the equilibrium position)
( as a result of upward velocity)
NOW, we have:

However;
means

also implies that:


Hence, 





Period can be calculated as follows:
= 
=
seconds
How many complete cycles will the mass have completed at the end of 4 seconds?
At the end of 4 seconds, we have:


cycles