Ep= mgh
Ep = 40 x 9.8 x 10
Ep = 3920J
Ep = 3900J (2sf)
D bc thats sound like the only resonable answer
The answer to this question would be B (the battery is the electrical power supply)
Answer:
Noise cancelling headphones have a microphone which listens to the ambient noise. The headphone then processes the sound and provides a wave to produce destructive interference. This cancels the ambient noise.
Explanation:
First, let us understand what interference is. Interference is the phenomenon that occurs when two waves superpose to form a wave which has a different wavelength, frequency, amplitude than the original two waves. When the crest of one wave superposes with the other waves crest then this results in the amplitude increasing. This is known as constructive interference. When the crest of one wave superposes with the other waves trough then this results in the amplitude decreasing. This known as destructive interference.
Noise cancelling headphones have a microphone which listens to the ambient noise. The headphone then processes the sound and provides a wave to produce destructive interference. This cancels the ambient noise.
It is fine to use the equation given by Plitter, since we are told that the mass is about the same as it is now, and I seriously doubt the original question wants the student to go into relativistic effects, electron degeneracy pressure and magnetic effects that govern a real white dwarf star.
There is no need to make it unnecessarily complicated, when the question is set at high school level. The question asks, given a particular radius, and a given mass, what will the density be (which in this case will be the average density). To answer the question, one needs to know the mass of the sun (which is about 2×1030 Kg. One needs to convert the diameter to a radius, and then calculate the spherical volume of the white dwarf. Then one can use the formula given above, namely density=mass/volume
