That is -300 J, because the work = the force times the distance. When the distance is a positive value when it is going down, the distance is a negative value when it is going up. The only thing that change is the minus, the absolute value of the work remains the same
<h2>
Answer: 3 - infrared light</h2>
Explanation:
<u>There are certain areas of the Milky Way that cannot be observed using the visible range of the electromagnetic spectrum</u> (this includes blue light and red light). This is because these areas are covered or hidden behind columns of interstellar dust and dark matter.
However, using infrared light and sometimes radio waves, it is possible to observe the galaxy better, because this light manages to pass through all that interstellar dust.
