Answer:
fo = 378.52Hz
Explanation:
Using Doppler effect formula:

where
f' = 392 Hz
C = 340m/s
Vb = 20m/s
Va = 31m/s
Replacing these values and solving for fo:
fo = 378.52Hz
Answer:
1020 km
Explanation:
A complete rotation of the wheel equals a distance of 1 circumference.
The circumference is

where <em>d</em> is the diameter of the wheel.
300,000 rotations = 
In kilometers, this is = 1017876/1000 km = 1020 km
Answer:
Oppositely charged particles attract each other, while like particles repel one another. Electrons are kept in the orbit around the nucleus by the electromagnetic force, because the nucleus in the center of the atom is positively charged and attracts the negatively charged electrons.
Explanation:
They are not the same event in that they occur in different places and times in most frames of reference. In the photon's frame they are not separated in either space nor time because photons don't experience time and at least mathematically all points on the spacetime manifold are the same point to a photon. What the zero spacetime interval can tell us though, is that the events are connected by a light beam (light-like separation). There is as much time between the events as there is space and one event can conceptually cause the other. They are on the cusp between time-like and space-like events.
Answer:
120 m/s if m/s means miles per second than
Explanation:
15 × 8