Math
posted by hhfo .
A certain mass is supported by a spring so that it is at rest 0.5 m above a table top. The lowest position of the mass is 0.1 m, and the highest position is 0.9 m. The mass is pulled down 0.4 m at time =0, creating a periodic up and down motion. It takes 1.2 s for the mass to return to the low position each time.
Determine the height of the mass above the table top after 0.7 s.

You need to know more than math to answer this question. It is about simple harmonic motion.
The amplitude of oscillation is 0.4 m and the period is 1.2 s.
The vertical height at time t is given by
y = 0.5  0.4 cos(2 pi t/1.2)
= 0.5 0.4 cos(5*pi*t/3)
To answer your question, use 0.7 for t.