A nitrogen atom with 7 protons and 8 neutrons has a mass number of 15amu however on the periodic table the atomic mass for nitrogen is 14.01
3 rd one because I had this on my test
Answer:
* First fight the reaction time of the person, which is approximately 1/10 s, remember that the stopwatch does not stop alone
* Problems to synchronize when starting to measure the oscillation and end point of the oscilloscope, this error needs a good control system to be decreased.
*Effect of friction with air
Explanation:
In the measurements of the oscillatory movement in general, the most difficult magnitude of the measurement is the period, by reasoning
* First fight the reaction time of the person, which is approximately 1/10 s, remember that the stopwatch does not stop alone
* Problems to synchronize when starting to measure the oscillation and end point of the oscilloscope, this error needs a good control system to be decreased.
* Effect of friction with air
Answer:
The first harmonic is: 250Hz, second harmonic 500Hz, third harmonic 750Hz.
Explanation:
Use the frequency f, speed v, and wavelentgh L relationship:

We are given the speed v=400 m/s. The base wavelength on a string of length 80cm is twice the length of the string (a "half wave" along the full length of the string), so:

The fundamental frequency (first harmonic) is 250 Hz
The second harmonic is produced by one full wave across the string (adding one node in the middle), so L=80cm in this case, therefore the second harmonic frequency is: f2 = 2*250=500Hz
the third harmonic add another node (and a half wave) to the pattern and the wavelength will be 2/3 of 80cm, so f3=3*250Hz = 750Hz
Current = (voltage) / (resistance)
Current= (3.0volts) / (9.8 ohms) =<em> 0.306 ampere</em> = 306 milliamperes (mA)