Answer:
The maximum temperature rise = 0.047 °C
Explanation:
Potential Energy, P = mgh
Energy transfered, Q=mcΔT
Potential energy = Energy transfered
mgh = mcΔT
gh = cΔT
ΔT = gh/c
ΔT = (9.81 * 20) / 4186
ΔT = 0.047 °C
Answer:

Explanation:
As we know that the acceleration of a point on the rim of the disc is in two directions
1) tangential acceleration which is given as

2) Centripetal acceleration

here we know that


now we know that net linear acceleration is given as

so we have


The center of mass is given with this formula:

Velocity is:

So, for the velocity of the center of mass we have:

In our case it is:
The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field.
Answer:
dam/hydro power
Explanation:
estuary is the place where rivers meet the ocean, there are a lot of currents there (waves...) so it likely means thery use a dam or some sort of way of collecting electricity from the motion of the water there. many birds live in estuaries because of being able to find fish to feed from