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.
What object do you need to match
To determine what the cyclists average speed is, simply divide the distance the cyclist has travelled by the time the cyclist has traveled for.
Assuming that this is the average rate the cyclist is moving at it would be 12 km/hr.
Answer:
134r kgm^-1 or 1344 kg /m
Explanation:
Momentum is is given by:
p=mv
Where:
p is momentum, m is mass in kg and v is velocity in ms−1
p=120kg×11.2 m/ s= 1344 kgms=1344kgm^−1
