Answer: 394 Hz
Explanation: this is a question under Doppler effect.
The mathematical equation that defines a Doppler effect is given below as
fo = {c+ vo/ c - vs} × f
Where fo = frequency observed =?
c = speed of sound = 345 m/s
vo = velocity of observer relative to source = 9.5m/s
vs = velocity of source relative to observer = - 9.5 m/s ( the negative sign is as a result of the fact that the observer and the source are moving in opposite direction to each other)
f = frequency of sound by source = 394 Hz.
By substituting the parameters, we have that
fo = {345 + 9.5/ 345 - (-9.5)} × 394
fo = (345 +9.5/ 345 + 9.5) × 394
fo = (354.5/354.5) × 394
fo = 1 × 394 = 394 Hz
Answer:
The potential energy can be given as
E = mgh. m is mass, g = acceleration due to gravity = 9.8m/s, h is the heigh, given as 100.0m
E = m x 9.8 x 100 = (980m)J
E = (980m)/10^9GJ = (0.000000980m)GJ to 3 significant figures
Explanation:
Hydroelectric dams exploit storage of gravitational potential energy. A mass, m, raised a height, h against gravity, g = 9.8 m/s², is given a potential energy E = mgh. The result will be in Joules if the input is expressed in meters, kilograms, and seconds (MKS, or SI units).
Answer:
the intensity of the sound waves produced by one 60-w speaker at a distance of 1.0 m is 60 w/m²
Explanation:
Intensity of sound , I, is given as;
I = P/A
Where;
P is the power through an area = 60-w
A is the area = ?
A = 1.0m × 1.0m = 1.0 m²
I = 60-w / 1.0 m²
I = 60 w/m²
Therefore, the intensity of the sound waves produced by one 60-w speaker at a distance of 1.0 m is 60 w/m²
C is the answer
D is impossible
A and B are false
Hope this helps!
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