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
Answer:
Korean War: 25 June 1950 – 27 July 1953
Many then believed that the conflict was likely to soon escalate into a full-scale war between the three countries, the US, the USSR, and China. CBS war correspondent Bill Downs wrote in 1951 that, "To my mind, the answer is: Yes, Korea is the beginning of World War III.
Explanation:
Answer:
a) The voltage on resistor R1 is less than before. Letter B.
b) The current through R1 is less than before. Letter B.
c) The resistance of the circuit went up by adding R2 in series. Letter A.
Explanation:
a) The new resistor R2 was added in series, that means the same current goes through both resistors (R1 and R2) and that the sum of the individual voltage drop of those resistors should be the same as the voltage of the source. Before there was only resistor R1 connected to the source, so all the voltage of the source was being delivered to that component, but now it is divided between R1 and R2. So the voltage on R1 is less than previously. Letter B.
b) A battery works as a voltage source, so assuming it's charged, it delivers a value of voltage to the circuit, while the current flow through it is defined by the equivalent resistance across the terminals. Since the new resistor was added in series the total resistance of the circuit went up and the current delivered by the battery went down. Letter B.
c) Since the equivalent resistance for a series connection is the sum of the resistors, R12 = R1 + R2, the resistence went up. Letter A.
