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How do you prove Kepler's Third Law?

For starters, what exactly is Kepler's Third Law? Kepler's Third Law states that the square of the time period of orbit is directly proportional to the cuber of the semi-major axis of that respective orbit. ...
DB
Answered by Daniel B. • Physics tutor
84168 Views

What is "half-life"?

Half-life is a term commonly used in radioactivity. It defines the time taken for a radioactive source to halve its activity. A radioactive source will emit radiation (energy) through the emission of particl...
ET
Answered by Evan T. • Physics tutor
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What are Balanced Forces?

An object experiances a force if it's pushed or pulled, and is measured in newtons. These forces are represented as arrows in force diagrams, these arrows give information on how big and in what direction th...
RA
Answered by Ross A. • Physics tutor
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A given star has a peak emission wavelength of 60nm, lies 7.10*10^19m away and the intensity of its electromagnetic radiation reaching the Earth is 3.33*10^-8Wm^-2. Calculate the star's diameter

With a problem like this, the key is to split it down into component parts. We will treat the star as a perfect emitter and radiator, something known as a black body. There will be two physical laws we need ...
JS
Answered by James S. • Physics tutor
5203 Views

Why is the sky blue?

The colour of the sky comes from sunlight scattering off of the air molecules (and to your eyes). Blue light gets scattered more than red light because it has a shorter wavelength, and so the light you see w...
AP
Answered by Alex P. • Physics tutor
9864 Views