There is no SI "base unit" of density.
(Any unit of mass) divided by (any unit of volume) is
a valid unit of density.
The units of density that are seen most often are
(gram per cm³) and (kgm per meter³) .
Answer:

Explanation:
From the exercise we know the cannonball's <u>initial velocity</u>, the <u>angle</u> which its released with respect to the horizontal and its <u>initial height</u>

If we want to know whats the <u>y-component of velocity</u> we need to use the following formula:

Knowing that 

So, the cannonball's y-component of velocity is 
Runner A because they completed it in a less amount of time
The absolute refractive index is equal to the speed of light of the wave in air divided by the speed of light in the second medium. This means that it is equal to 3 x10^8 / 1.71 x10^8. This means the answer is 1.75