Earth's atmosphere blocks many types of light including gamma, x-rays most ultraviolet and infrared. So optical telescopes that use visible light and ultraviolet telescopes that are used to study very hot stars are much less effective on Earth.
Answer:

Explanation:
The change in kinetic energy will be simply the difference between the final and initial kinetic energies: 
We know that the formula for the kinetic energy for an object is:

where <em>m </em>is the mass of the object and <em>v</em> its velocity.
For our case then we have:

Which for our values is:

Explanation:
For an experimental result to be considered acceptable, all relevant variables involved in the experiment must be taken into account, by isolating it, performing it under controlled conditions and modifying the conditions under which it takes place. This, with the objective of excluding alternative explanations in the analisis of the experimental data. Therefore, if these steps are followed appropriately, experimental data are trustworthy. The reliability of the experiment increases when it is replicated by other researchers and the same results are obtained.
Technically you can go forever on and on, but maybe your question was like how many rotations in a certain distance?
Answer:
In 0.5 seconds.
Explanation:
The time would be the same because it only depends on the height and the vertical component of the initial velocity. This is of course because each direction must be treated independently. Since between both cases only the horizontal speed changes, the height is the same and the vertical component of the initial velocity is null for both, the time to fall is the same.