Answer:
Explanation:
Given:
- thickness of the base of the kettle,
- radius of the base of the kettle,
- temperature of the top surface of the kettle base,
- rate of heat transfer through the kettle to boil water,
- We have the latent heat vaporization of water,
- and thermal conductivity of aluminium,
<u>So, the heat rate:</u>
<u>From the Fourier's law of conduction we have:</u>
where:
area of the surface through which conduction occurs
temperature of the bottom surface
is the temperature of the bottom of the base surface of the kettle.
Eris is slightly more massive than Pluto. However, both of them are smaller than Earth's Moon.
This should conclude that Eris is a dwarf planet.
Answer:
- Direct current is a current in which electrons flow in one direction only
- Alternating current is a current in which the direction of the electron flow reverses periodically - so, half a cycle forward, half a cycle backward
There are several advantages of using alternating currents for the transmission of electricity across a country, over large distances. The main advantages are:
- The voltage of alternating currents can be easily increased/decreased by using transformers. For instance, a transformer is used at the beginning of the transmission line to increase the voltage (electricity is transmitted at high voltage in order to reduce dissipated power), and then another transformer is used before the electricity enters the houses, in order to decrease the voltage. Transformers only work with alternating currents.
- It is easy to interrupt the flow of an alternating current, because its value naturally becomes zero every half a cycle, so this is useful in case the current must be interrupted.
Answer:
5.51 m/s^2
Explanation:
Initial scale reading = 50 kg
assume the greatest scale reading = 78.09 kg
<u>Determine the maximum acceleration for these elevators</u>
At rest the weight is = 50 kg
Weight ( F ) = mg = 50 * 9.81 = 490.5 N<u>
</u>
<u>
</u>At the 10th floor weight = 78.09 kg
Weight at 10th floor ( F ) = 78.09 * 9.81 = 766.11 N
F = change in weight
Change in weight( F ) = ma = 766.11 - 490.5 (we will take the mass as the starting mass as that mass is calculated when the body is at rest)
50 * a = 275.61
Hence the maximum acceleration ( a ) = 275.61 / 50 = 5.51 m/s^2
