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:
There is no mechanical advantage
Explanation:
The mechanical advantage is possible only when the force needed to lift a load is lesser than the weight of the load.
For example, is we have a mechanical advantage of 2, the force needed to lift will be 1/2 of the weight of the load, and if we have a mechanical advantage of 4, the force needed will be 1/4 of the weight of the load.
In the attached image there are clear examples of mechanical advantage with pulleys.
When the car moves and makes a sound that is louder that when the car is just sitting there
Newton's first law of motion.
They have the same Number of protons
