What is the difference between a rock and a mineral? Minerals contain fossils while rocks do not.
A mineral is an inconsistent mixture of rocks, while a rock is "pure" and made up
of a precise combination of minerals.
O A rock is harder than all minerals.
A rock is an inconsistent mixture of minerals, while mineral is "pure" and made
up of a precise combination of chemicals.

PLEASEEE HELPPP

A rock is an inconsistent mixture of minerals, while mineral is "pure" and made  up of a precise combination of chemicals.

Explanation:

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.

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