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: 15m/s
Explanation: <u>Average</u> <u>Velocity</u> is vector describing the total displacement of an object and the time taken to change its position. It is represented as:
At t₁ = 1.0s, displacement x₁ is:
x(1) = 28
At t₂ = 4.0s:
x(4) = 73
Then, average speed is
v = 15
The average velocity of a car between t₁ = 1s and t₂ = 4s is 15m/s
Answer:
demand (an amount) as a price from someone for a service rendered or goods supplied.
Answer: Yes.
Explanation:
There is gravity in water because How does the water go up in the cycle? the garavity with the wind pull it up.
