Answer:
Explanation:
All the rest of the information is extraneous. The only 2 things you have to know are
d = 20 km
t = 8 minutes = 8/60 hours = 0.13333333
So the speed is s = d/t
s = 20/0.1333333 = 150 km/hour
Note: you have not specified what units the speed is. I suppose you could answer 20/8 = 2.5 km/min
Answer:
Final volumen first process 
Final Pressure second process 
Explanation:
Using the Ideal Gases Law yoy have for pressure:

where:
P is the pressure, in Pa
n is the nuber of moles of gas
R is the universal gas constant: 8,314 J/mol K
T is the temperature in Kelvin
V is the volumen in cubic meters
Given that the amount of material is constant in the process:

In an isobaric process the pressure is constant so:



Replacing : 

Replacing on the ideal gases formula the pressure at this piont is:

For Temperature the ideal gases formula is:

For the second process you have that
So:




Answer:
The visible light frequency is 400 THz to 700 THz, approximately. A THz is a Terahertz, which is a unit of frequency equal to one trillion Hertz.
Answer:
Revolving nosepiece
Explanation:
The revolving nosepiece is one of the parts of a microscope, used for holding the objective lenses. They can be turned to put a particular objective lens in place to be used in order to vary magnification.
The colour we see is a measure of the wavelengths of light nor absorbed by the cloth. We would call the colour of the cloth blue if it absorbed longer wavelengths of yellow/orange/red. Sunlight contains all the visible wavelengths. Whatever is not absorbed is reflected.