Answer:
According to the travellers, Alpha Centauri is <em>c) very slightly less than 4 light-years</em>
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Explanation:
For a stationary observer, Alpha Centauri is 4 light-years away but for an observer who is travelling close to the speed of light, Alpha Centauri is <em>very slightly less than 4 light-years. </em>The following expression explains why:
v = d / t
where
- v is the speed of the spaceship
- d is the distance
- t is the time
Therefore,
d = v × t
d = (0.999 c)(4 light-years)
d = 3.996 light-years
This distance is<em> very slightly less than 4 light-years. </em>
The elastic potential energy (Ep) is given by
Data:
Ep = ? (Joule)
k = 20 N/m
x (displacement) = 0.20 m
Solving:
Base on my research, as of 2004 The U.S. devours about 20 million barrels of oil a day, according to the CIA. But base on Wikipedia, it says that a normal large tanker can only carry around 2 million barrels of oil. So to supply the U.S with this oil per day, it needs 10 normal large oil tankers.
The correct answer is D: Watt. This unit was named after James Watt, and
is used to express the equivalent of one joule per second in energy. In
experiments and on the packaging for electrical products such as light-bulbs, the measurement will usually be written in its abbreviated
format: W.
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