Answer:
B. 22 Hz and 42 Hz
Explanation:
The beat is an interference pattern which occurs when two waves of slightly different frequencies meet each other. The beat is heard as a periodic variation, whose frequency (called beat frequency) is equal to the absolute value of the difference between the frequencies of the individual waves:
In this problem, we are told that 20 beats per second are produced, so the beat frequency is
Therefore, we must find the two waves which have a difference in frequency equal to this value, 20 Hz. Let's see each choice:
A. 38 Hz and 63 Hz --> --> NO
B. 22 Hz and 42 Hz --> --> YES
C. 47 Hz and 55 Hz --> --> NO
D. 18 Hz and 26 Hz --> --> NO
So, the correct choice is
B. 22 Hz and 42 Hz
To solve this problem it is necessary to apply the concepts related to stress failure, stress and last module Young.
Critical stress by definition is given as,
Where,
Strain fracture toughness
Y = Young's module
a = Length surface crack
Our values are given as,
Replacing in our previous equation we have,
Therefore the critical stress is 984.77Mpa
A uniform thin solid door has height 2.20 m, width .870 m, and mass 23.0 kg. Find its moment of inertia for rotation on its hinges. Is any piece of data unnecessary? So far, I don't understand how to calculate moments of inertia for things like this at all. I can do a system of particles, but when it comes to any ridgid objects, such as this door or rods or cylinders, I don't get it. So basically I have no idea where to even start with this.
so A
Answer:
It's A
Explanation:
Although I'm not sure about the second one, I'm sure the first one is A
Answer:
Wavelength,
Explanation:
In an electromagnetic wave both electric and magnetic field propagate simultaneously. Radio waves, microwaves, gamma rays etc are some of the examples of electromagnetic waves.
If f is the frequency of electromagnetic wave, c is the speed of light, then the relationship between the frequency f, wavelength and the speed is given by :
Hence, the correct option that shows the wavelength of electromagnetic wave in free space is(a) " c/f ".