GS-2 Physical Sciences Question 48

[fussion_106672]

48. If an object is made to resonate, which of the following properties of the system is not at its maximum?

1. Power
2. Energy
3. Amplitude
4. Speed


correct answer: Energy and power are both proportional to the square of the amplitude

Can you show me the formulas that relates energy and power to amplitude?

Thanks.

[mcat_premed3832]

The relationship as described in the Explanation is required knowledge for the new MCAT but the equation which is far more complicated is not required knowledge. This relationship is described in PHY 8.3 in The Gold Standard MCAT. You will also find below 2 sources which discuss the relationship but do not present the equation because it is beyond introductory level knowledge (the pages are long so you can do CTRL F and then "square of" to find the relevant information).

http://www.indiana.edu/~emusic/acoustics/amplitude.htm

http://www.acoustics.salford.ac.uk/feschools/waves/propagation.htm

[StoneColdPS14]

another poorly constructed question with no meaningful explanation.
by the way, the pages u linked to have no relevant discussion. and just to spike you, any resonating system, or simple harmonic motion of the wave, the object will reach its maximum velocity when passing through the equilibrium point.

[nedaa.asba6809]

Here are the equations that relate energy, power, and amplitude:

E = ½ k A^2, where E = is the energy, k = is the wave number, A = is the amplitude.

P = ½ μ ω^2A^2v, where ω = is the angular frequency, P = is the power, v = is the velocity.

Please note that you do not need to memorize these equations

[mcat_premed3832]

Please note: this type of question is relatively common on the new MCAT. Some might see it as a "most correct" type of question but their real focus is to ensure that you know the most common relations (but please don't take those equations seriously!; only memorize these ones: www.goldstandard-mcat.com/physics-equation-lists). In medicine, we call it "pattern recognition" and after you do all of the GS and AAMC tests, and review them properly, you will understand what they are looking for, quite often, before you are finished reading the question. But still read it!!!

[admin]

Bump.