I think it would be the one talking about if there’s water there would still be energy because water is used as a source of energy because there’s so much of it and it can be used again and again
1) The half-life is the time required for a substance to reduce to half its initial value. In formulas:
(1)
where
m(t) is the amount of substance left at time t
m0 is the initial mass
is the half-life
In this problem, the half-life of the substance is 20 years:
therefore, the fraction of sample left after t=40 years will be
So, only 1/4 of the original sample will be left, which corresponds to 25%.
2) We can use again formula (1), by re-arranging it:
If we use m(t)=10 g (mass of uranium left at time t), and
(the time is equal to 4 half lifes), we get
So, the initial sample of uranium was 160 g.
<u>D: Half</u>
We know that,
F = m.a, where F is the force, m is the object's mass and a is the acceleration.
In the first case, we observed that a1 = F/m.
In the second case, we observed that the mass has been doubled, so a2 = F/2m .
By the ratio of the two cases, we get
a1/a2 = F/m / F/2m
or, a1/a2 = 2
or, a1 = 2.a2
or, a1/2 = a2
Therefore, the acceleration gets <u>half</u> of it's original measurement.
<u> </u> <span><span> No. Neutron stars are the remnants of very large stars that have supernova'd. Anything below 1.44 solar masses becomes a dwarf, anything above 5 solar masses becomes a black hole. Everything in between becomes a neutron star (or quark star, but it's not proven).</span>
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