Over time, the types of technology can vary and be improved upon so that more advanced techniques become more valued. This could be the situation with mining whereby back in the 1500's in underground mines the rock was broken by fire setting ie lighting a fire below the rock face to heat up the rock and then throwing cold water on it to crack it, so that it could be dug by hand. With the advent of explosives, this all changed so that the rock could be blasted. The increase in advance rates for an underground heading have thus gone from 5-20 feet per month to up to 300meters (984 ft) per month for a 24/7 mining operation, which is a huge improvement.
There was a supercontinent called Pangea
Answer:
A line of symmetry is a line that separates a shape into two identical halves.
Rotational symmetry is the same thing except when you rotate the object, it has to have the exact same line of symmetry.
<u><em>Hope this helps!!!</em></u>
Is the variable you change, independent, I, something I change.
Answer:
time=4s
Explanation:
we know that in a RL circuit with a resistance R, an inductance L and a battery of emf E, the current (i) will vary in following fashion
, where 
max=
Given that, at i(2)=
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Applying logarithm on both sides,
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Now substitute 
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Applying logarithm on both sides,
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now subs.
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also 
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