The Moon orbits the Earth at an average distance of 3.84 105 km with an orbital period of 0.07481 yr. Neptune, which is one of the satellites of the Sun, orbits its parent at an average distance of 4.50 109 km with an orbital period of 164.8 yr. (a)
Use the above information to find the orbital speeds of the Moon around the Earth and of Neptune around the Sun.
vMoon
= m/s
vNeptune
= m/s
(b)
What is the expression for the mass M of the parent in terms of the orbital speed v of the satellite, the orbital radius R of the satellite and the gravitational constant G? (Do not substitute numerical values; use variables only.)
M =

Consider Newton's Universal Law of Gravitation. What supplies the centripetal force needed for the satellite to go around its parent?
(c)
Now use your answers from parts (a) and (b) to find the ratio of the mass of the Sun to that of the Earth.

the area between the graph and the t axis

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

answera compound;