Answer:
A rover uses 4GHz frequency to transmit a picture. The rover’s transmission power is 200W. Distance = 55*10^9m. The transmission antenna gain is 10,000 and the receiving antenna gain is 100,000. What is the received signal strength at the Earth’s station, in W (assume Pi = 3.14)?
= 31.5 db
Explanation:
Path loss = 20㏒₁₀(4πdf / c)
= 20㏒₁₀(d) + 20㏒₁₀(f) - 20㏒₁₀(4π / c)
= 20㏒₁₀(55 × 10⁹) + 20㏒₁₀(4000) - 147.5
= (20 × 77.4) + 20 × 3.6 - 147.5
= 154 + 72 - 147.5
= 78.5 DB
Received signal strength(power)
Pr = Pt + Gt + Gr - Lp dBW
= 20 + 40 + 50 - 78.5
= 31.5 db
A) 
The energy stored in a capacitor is given by:
where
Q is the charge stored
C is the capacitance
The capacitance of a parallel-plate capacitor is
where
is the vacuum permittivity
is the area of each plate
is the distance between the plates
Substituting,
The charge stored on the capacitor is
So, the energy stored is
B) 
This time, the separation between the plates is
d = 1.7 mm = 0.0017 m
So, the new capacitance is
And so, the new energy stored is
C)
Energy must be conserved, so the difference between the initial energy of the capacitor and its final energy is just equal to the work done to increase the separation between the two plates from 1.5 mm to 1.7 mm (in fact, the two plates of the capacitor attract each other since they have opposite charge, so work must be done in order to increase their separation)
Answer:
Inclined plane.
Explanation:
Geometrically, a screw is a narrow inclined plane that is wrapped around a cylinder. Like the other simple machines a screw can amplify force; a small rotational force (torque) on the shaft can exert a large axial force on a load.
A screw is a cylinder with a head (solid top) at one end and a pointed tip (like a nail) at the other end.
The mechanical advantage of the screw depends on the space between the threads and the length (and thickness) of the screw. The closer the threads are, the greater the mechanical advantage. It is easier to drive a screw into an object if the thread spacing is smaller.
Well this is just my opinion but I think because all the plants were gone they cant stop mud from rolling into it. Also when it rains the trees wont suck up the water, that will make it over flow and release into the land or dirt on the outsides of it. Mixing those two gives mud and it can potentially flow back in the river in largeish masses causing the river to mix with the mud makinging it more muddy. Hope this helps :D
