Which of the following statements does not correctly describe a harmonic plane wave traveling in some medium.
1 answer:
Answer:
Incorrect statement is (b).
Explanation:
Option (a) : There is an inverse relation between the time and the frequency. The time taken depends on the frequency of the number of oscillations. Statement 1 is correct i.e. the time taken by any point of the wave to make one complete oscillation does not depend on the amplitude.
Option (b) : Speed of a wave is given by the product of its frequency and wavelength. It is not necessary that doubling the wavelength of the wave will halve its frequency as speed depends on the medium.
Option (c) : Doubling the amplitude has no effect on on the wavelength as amplitude does not depends on its wavelength.
Option (d) : Since,
Speed is directly proportional to the frequency and wavelength. So, doubling the frequency of the wave will double its speed. So, the incorrect statement is (b).
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To solve the problem it is necessary to apply conservation of the moment and conservation of energy.
By conservation of the moment we know that
Where
M=Heavier mass
V = Velocity of heavier mass
m = lighter mass
v = velocity of lighter mass
That equation in function of the velocity of heavier mass is
Also we have that
On the other hand we have from law of conservation of energy that
Where,
W_f = Work made by friction
KE = Kinetic Force
Applying this equation in heavier object.
Here we can apply the law of conservation of energy for light mass, then
Replacing the value of
Deleting constants,
Answer:
The resultant velocity of the plane relative to the ground is;
150 kh/h north
Explanation:
The flight speed of the plane = 210 km/h
The direction of flight of the plane = North
The speed at which the wind is blowing = 60 km/h
The direction of the wind = South
Therefore, representing the speed of the plane and the wind in vector format, we have;
The velocity vector of the plane = 210.
The velocity vector of the wind = -60.
Where, North is taken as the positive y or direction
The resultant velocity vector is found by summation of the two vectors as follows;
Resultant velocity vector = The velocity vector of the plane + The velocity vector of the wind
Resultant velocity vector = 210. + (-60.
) = 210.
- 60.
= 150.
The resultant velocity vector = 150.
Therefore, the resultant velocity of the plane relative to the ground = 150 kh/h north.