Which of the following statements about gemstones is true? choose one:

a. emerald is a gemstone variety of the common mineral corundum.
b. in order to be considered precious or semiprecious, a gemstone must be transparent.
c. a gemstone is a variety of a mineral that has value because of its color.
d. many gemstones come from pegmatites, which are particularly coarse-grained igneous rocks.

D

Explanation:

Emerald is not a variety of corundum rather its a variety of beryl.

A precious or semiprecious stone may or may not be transparent.

The value of gemstone is derived mostly by its rarity.

Pegmatite are igneous rocks found underground near sheets of igneous rocks called batholiths. They are a source of gemstones made of topaz, tourmaline, beryl spodumene and spessartine.

we're given that v₀ = 0 and a = 5.4 m/s². therefore, since v = at + v₀ for constant acceleration the equation for velocity is

after 28s,

m/s

which i would round to 150 m/s as my final answer