Both are
indicators of the chemical composition of silicate minerals, magmas and rocks.
Mafic is
used for silicate minerals, magmas and rocks that are composed of heavier
elements, like magnesium, iron, calcium and sodium. They are dark and have high
specific gravities.
<span>Opposite to
the this, felsic silicate minerals, magmas and rocks in their composition have
less from these heavy elements. They are composed from silicon, oxygen,
aluminium and potassium, are light in color and have lower specific gravities.</span>
Answer:
135 cm²
Step-by-step explanation:
The area (A) of a trapezoid is calculated as
A = h(a + b)
where h is the height and a, b the parallel bases
Here h = 9, a = 13 and b = 17 , thus
A = × 9 × (13 + 17)
= 0.5 × 9 × 30
= 135 cm²
The position function of a particle is given by:
The velocity function is the derivative of the position:
The particle will be at rest when the velocity is 0, thus we solve the equation:
The coefficients of this equation are: a = 2, b = -9, c = -18
Solve by using the formula:
Substituting:
We have two possible answers:
We only accept the positive answer because the time cannot be negative.
Now calculate the position for t = 6: