Physics- damon, Monday, December 1, 2014 at 3:27 pm force =change in momentum\ change in time or m a if m is constant
change in momentum/3=200
change in momentum =3*200 kg m/s
Electronegativity is the measure of the tendency of an atom to attract a bonding pair of electrons. In the periodic table, electronegativity increase across the period because the charges on the nucleus increase. The correct arrangement for the atoms given above is as follows
Flourine and Francium
Chlorine and Cesium
Nitrogen and Sodium
Phosphorus and Lithium
Nitrogen and Sulphur.
<u>Answer</u>
5.the stage before a star becomes a main sequence star
<u>Explanation</u>
A protostar is a small star that is still gathering its masses. When it forms enough masses it make a parent molecular cloud.
This been the case, from the choices given, the correct statement about a protostar is;
5.the stage before a star becomes a main sequence star
Answer:
B) waves speed up
C) waves bend away from the normal
Explanation:
The index of refraction of a material is the ratio between the speed of light in a vacuum and the speed of light in that medium:

where
c is the speed of light in a vacuum
v is the speed of light in the medium
We can re-arrange this equation as:

So from this we already see that if the index of refraction is lower, the speed of light in the medium will be higher, so one correct option is
B) waves speed up
Moreover, when light enters a medium bends according to Snell's Law:

where
are the index of refraction of the 1st and 2nd medium
are the angles made by the incident ray and refracted ray with the normal to the interface
We can rewrite the equation as

So we see that if the index of refraction of the second medium is lower (
), then the ratio
is larger than 1, so the angle of refraction is larger than the angle of incidence:

This means that the wave will bend away from the normal. So the other correct option is
C) waves bend away from the normal