Radio waves have many uses—the category is divided into many subcategories, including microwaves and electromagnetic waves used for AM and FM radio, cellular telephones and TV.
The lowest commonly encountered radio frequencies are produced by high-voltage AC power transmission lines at frequencies of 50 or 60 Hz. These extremely long wavelength electromagnetic waves (about 6000 km) are one means of energy loss in long-distance power transmission.
Extremely low frequency (ELF) radio waves of about 1 kHz are used to communicate with submerged submarines. The ability of radio waves to penetrate salt water is related to their wavelength (much like ultrasound penetrating tissue)—the longer the wavelength, the farther they penetrate. Since salt water is a good conductor, radio waves are strongly absorbed by it; very long wavelengths are needed to reach a submarine under the surface.
HOPE THIS REALLY HELPS YOU.
THANK YOU.
A). Her distance traveled was (700m + 500m) = <em>1,200 meters</em>
B). Her displacement was (700m north + 500m south) = <em>200 meters north</em>
C). Her average speed = (distance covered) / (time to cover the distance)
Speed = (1,200 meters) / (15 seconds)
<em>Speed = 80 meters/second</em>
(Layne is an incredible walker ! That's about 179 miles per hour.)
(She walks 700m in 10 seconds. Usain Bolt runs only 100m in 10 seconds.)
D). Her averge velocity = (displacement) / (time)
Velocity = (200 meters north) / (15 seconds)
<em>Velocity = (13 and 1/3) m/s north</em>
(This is only about 33% faster than Usain Bolt, if he went straight instead of doubling back, and if he could keep it up for 200 meters instead of only 100 meters.)
Answer:
Maximum height, h = 11.32 meters
Explanation:
It is given that,
The baseball is thrown directly upward at time, t = 0
Initial speed of the baseball, u = 14.9 m/s
Ignoring the resistance in this case and using a = g = 9.8 m/s²
We have to find the maximum height the ball reaches above where it leaves your hand. Let the maximum height is h. Using third equation of motion as :
At maximum height, v = 0
and a = -g = -9.8 m/s²
h = 11.32 meters
Hence, the maximum height of the baseball is 11.32 meters.
Answer:
An electric motor converts electrical energy into mechanical energy. The process is as follows:
D. When current flows through the motor, it powers electromagnets that are attracted and repelled by the poles of permanent magnets in the motor. The movement of the electromagnets turns a rod in the motor, which makes the mechanical energy available.