Question

When using the Vertical motion model, where does the leading coefficient -16 come from? When will it not be -16 and how will you know?

I'm just trying to understand the Model.

Answer 1

the -16 comes from the acceleration due to gravity. That is -32 ft/s^2.

The general form starting at height h with upward velocity v is

s(t) = h + vt + 1/2 at^2

where a is negative, since gravity pulls downward.

Answer 2

g = -32 ft/s^2 in the feet (old American - English) system so (1/2)g = -16
Watch out, most of us use metric units
g = -9.81 m/s^2
in which case
h = Hi + Vi t - 4.9 t^2