This sounds pretty easy, in fact. The orbital motion can be assumed to be circular and with constant speed. Then, the period is the time to do one revolution. The distance is the length of a revolution. That is 2*pi*R, where R is the distance between the Moon and the Earth (the respective centers to be precise). In summary, it's like a simple motion with constant speed:
v = 2*pi*R/T,
you have R in m and T is days, which multiplied by 86,400 s/day gives T in seconds.
Then v = 2*pi*3.84*10^8/(27.3*86,400) = 1,022.9 m/s ~ 1 km/s (about 3 times the speed of sound :)
For the Earth around the Sun, it would be v = 2*pi*149.5*10^9/(365*86,400)~ 29.8 km/s!
I know it's not in the problem, but it's interesting to know how fast the Earth moves around the Sun! And yet we do not feel it (that's one of the reasons some ancient people thought crazy the Earth not being at the center, there would be such strong winds!)
Answer:
microwaves
Explanation:
Electromagnetic waves consist of waves of different wavelengths. Among the choices given, waves are ordered for increasing wavelengths as follows:
gamma rays --> ultraviolet waves --> infrared waves --> microwaves
So, microwaves are the waves with the longer wavelength among the given choices. This is the reason why they are used by the cell phone companies: in fact, since they have longer wavelengths, microwaves can travel longer distances without being absorbed by objects or obstacles, and so they are more reliable for broadcasting and telecommunications.
Answer:
0.25A
1.0A
2.5A
Explanation:
this is only for the calculated current column on edge
Answer:
- So, the force its
N to the west.
Explanation:
The force 
on a charge q made by an electric field 
its
The electric charge of the electron its
.
Taking the unit vector 
pointing towards the east, the electric field will be:
.
So, the force will be:
So, the force its N to the west.
Answer:<u><em>B. Temperature</em></u>
Explanation:The temperature of the star such as Sun is measured. Using this measurement, its peak wavelength and energy can be determined.For determination of wavelength, <u>Wien's displacement law is used</u>. This law states that, the sun like body emits all kinds of wavelengths and thus is nearly a black body.For black body, the peak wavelength emitted is inversely proportional to the temperature of the body. From the wavelength, energy can be calculated.<u>Temperature is the property which is primarily responsible for determining the type of electromagnetic energy and peak wavelength emitted by star</u>.
