Answer:
1.Ultrasound is a mechanical wave
2.Ultrasounds are sound waves having a frequency above 20,000Hz
3.ltrasound is not included in the electromagnetic spectrum
4.An ultrasound scan uses high-frequency sound waves to create images of the inside of the body
5.Therapeutic ultrasound has no known harmful effects when done right by your therapist
The best place to put PFDs while you are out on your boat is at the top deck of your boat. PFDs must be placed at an area where it is easily accessible, especially in times of accidents, without any unnecessary gear or objects covering the PFDs, but it is best to wear a life jacket during the whole duration of the boat trip.
Answer:
(a). The net gravitational force is 
(b). The position is at 0.232 m.
Explanation:
Given that,
Mass of one object M = 255 kg
Mass of another object M'= 555 kg
Separation = 0.390 m
(a). We need to calculate the net gravitational force
Using formula of force


Put the value into the formula


The net gravitational force is 
(b). We need to calculate the position
Force from 555 mass = Force from 255 mass




The position is at 0.232 m.
Hence, (a). The net gravitational force is 
(b). The position is at 0.232 m.
The one that help create radio waves is :
Changing electric and magnetic fields applied at right angles
Radio waves are transverse wave, which means that the oscillations occurring perpendicular to the direction of energy transfer
hope this helps