Answer:
<u>because of the doppler effect</u>
Explanation:
<em>Remember</em>, the doppler effect refers to the changes in sound (frequency of sound) observed by a person who is in a position relative to the wave source.
In this example, we notice as the train comes closer to the boy, the sound becomes louder also increasing the pitch slightly, the doppler effect sets in when the train passes the boy because the boy notices a decrease in the pitch of the moving train.
We learn from the change in the observed sound of the train that the frequency of the sound is determined by the distance of the observer from the wave source.
In other words, the closer the source of the sound to the observer; the faster it travels to the observer, however, the farther it is; the lesser it is; the greater the sound heard.
Answer:
2.7067 eV
Explanation:
h = Planck's constant = 
c = Speed of light = 
= Threshold wavelength = 459 nm
Work function is given by
Converting to eV
The work function W0 of this metal is 2.7067 eV
The hardest part of the job is to find the right formula to use, and write it down. You've already done that ! The rest is just turning the crank until an answer falls out.
You wrote. E = m g h.
Beautiful.
Now divide each side by (g h), and you'll have the formula for mass:
m = E / (g h).
You know all the numbers on the right side. Just pluggum in, do the arithmetic, and you'll have the mass.
Potential and kinetic energy are the two types of energy, but they do get separated into subgroups, for which I do not know. Hope that helps.
Answer:
The time it can operate between chargins in minutes is
Explanation:
Given: 
, 
, 
a). The rotational kinetic energy
b). The power average 0.8kW un range time can be find
Solve to t'
