Answer:

Explanation:
Density can be found by dividing the mass by the volume.

The mass of the quartz is 30 grams and the volume is 6 cubic centimeters.

Substitute the values into the formula.

Divide.

The density of this piece of quartz is 5 grams per cubic centimeter.
Answer:
v = 1.4 m /s
Explanation:
We shall apply law of conservation of mechanical energy
The kinetic energy of dart and block is converted into potential energy of both dart and block .
1 /2 (m+M) v² = ( m +M) gH
.5 x v² = 9.8 x .1
= v² = 1.96
v = 1.4
v = 1.4 m /s
free lil peezy and drake is kool
Answer:

Explanation:
Given the parallex of the star is 0.1 sec.
The distance is inversely related with the parallex of the star. Mathematically,

Here, d is the distance to a star which is measured in parsecs, and P is the parallex which is measured in arc seconds.
Now,

And also know that,

Therefore the distance of the star is
away.