Answer:
I will answer this in English, we can translate it to:
Why if you charge a mate by an amount of time you are not doing work?
This happens because work is defined as the displacement done by a force:
W = d*F
where W is work, d is the distance, and F is the force.
This means that the amount of time that you are charging your mate does not affect the mechanical work, the only time that you are doing work is when you are lifting him.
Answer:
Sound waves are longitudinal in nature.
Explanation:
There are many types of waves like transverse, longitudinal, electromagnetic wave etc.
Sound waves are longitudinal in nature. In longitudinal type of wave, the medium particles moves parallel to the propagation of the wave. This type of waves move in the form of compression and rarefaction.
In compression, the particle density at a point is very less while in rarefaction, the particle density at a point is very high.
So, the correct option is (b) "longitudinal wave".
AC reverses the current in periods, and the current flows in 2 directions.
DC only flows in one direction and is constant.
AC is typically used to transfer power over long distances from a generator to your home, stepping it up after it's generated to send it over the distance, then stepping it back down so that it is usable in your home.
DC is used typically inside of devices, as it sends a certain amount of electricity through the wires.
Nicolas Tesla, was ripped off by Edison to replace his DC stations with AC instead. ^^
They keep the astronauts safety as a priority. They also try to stay in budget, but mainly the astronauts safety is most important.
