<span> When a gas is cooled, it contracts. In a sealed environment, the pressure would therefore reduce, as the molecules try to get closer together, that is, push outwards less. But in the atmosphere, the closer-packed molecules (or atoms, of course) make the air more dense, therefore heavier.
If you were at a higher elevation, the cooling is caused by the reduced pressure causing the molecules to move further apart. The temperature reduces about 1 degree Centigrade for every 100metres gain in elevation.
Any good? </span>
This would prove that gold is an <em>element</em>. No matter how far down you
examine it, you never find any particles of anything except gold.
An example of a different case is salt.
-- Imagine you had a block of salt and decided to cut it in half.
-- If you repeated this process, then eventually, at some point, you'd have
a tiny particle of salt in front of you, just like before. BUT ...
-- Just as you were getting ready to cut this one in half, you'd notice that this
particle of salt is different. It's one atom of sodium stuck to one atom of chlorine,
and if you cut it in half, you would not have ANY salt. <span />
This would prove that salt is a <em><u>compound</u></em>, made of atoms of two or more elements.
Answer:
Correct answer: W = 2,240 J
Explanation:
Given:
m = 70 kg
V₁ = 6 m/s
V₂ = 10 m/s
W = ?
Work is a measure of change in this case of kinetic energy:
W = ΔE = (m V₂²)/ 2 - (m V₁²)/ 2 = (m / 2) · (V₂² - V₁²)
W = (70 / 2) · (10² - 6²) = 35 · (100 - 36) = 35 · 64 = 2,240 J
W = 2,240 J
God is with you!!!