Probably for kind of the same reason that speed is expressed as a
relationship between two units. You know, like miles per hour .
I guess the only reason is because no single unit has been invented
to describe density.
The rate of doing work or using energy would always be expressed
as a relationship between two units ... we would say that the rate of
work is "(so many) joules per second". But the "watt" was invented,
so we can say "(so many) watts" instead.
So I guess you're right. Density could be simpler to describe
if we only had a unit for it. Then we wouldn't have to say "(so many)
grams per cubic centimeter". We would just say "(so many) (new unit)".
Let's try it out:
"Uhhh, pardon me Professor . . . I've been working late in the lab,
and I believe I've identified a new substance, hitherto unknown to
the scientific community, and totally unexpected. In its pure form,
the substance appears to be pink, it smells like butterscotch, and
its density is approximately 27.4 Brianas. I think it's time we published
these findings ... with your name as lead investigator, of course."
I like it !
Volume by Displacement. The displacement method (submersion, or dunking method) can be used to accurately measure the volume of the human body and other oddly shaped objects by measuring the volume of fluid displaced when the object is submerged.
The following precautions should be taken very observantly:-
The line of sight must be perpendicular to measuring scale to avoid parallax error. Formation of bubbles inside the cylinder should be completely avoided. Any bubbles within leads to wrong measurements.
It would be option C. It rotates, or spins, on its axis, but it revolves around the sun.
Explanation:
Bulbs are nothing but resistors that glow when current passes through them.
In Set A, the bulbs (resistors) are connected parallely to each other, this means that even if one of the bulbs fuses or removed, the circuit will still be completed and others continue to glow.
And in parallel connection if the resistance of the two resistors are same powered delivered to each is same.
In Set B, bulbs are in series connection, this means that when one of the bulb is removed or fuses, the circuit will break and other bulbs can not operate.In this situation as well if the resistance of two resistors is same then the power delivered is same.