Question 50

[matthew]

Dear Dr. Ferdinand,

In the solutions they used 10^3 for density but why can't it be 1kg/m^3 everything else has meters in it.

wouldn't it be more appropriate to use the 1 kg/m^3 rather than using the 1cm *1000 to 1kg. I don't understand the conversion being necessary if nothing else is in cm and would need to convert.

Problem kind of confusing. But I looked up the units of Pascal's thinking maybe it might have cm in it, said N/m^2. and a Newton has kg*m/s^2 in it.

[admin]

Approx. every 3rd MCAT requires you to know the density of water: everyone remembers 1 g/ml or 1 g/cc or 1 g/cm^3 but did you know that if you use dimensional analysis that converts to 1000 kg/m^3? One more interesting point to add to your memory banks! Keep up the good work!

[h99h20baby]

where are you gettting the Po to be 10^5?? I am confused!

[admin]

Po is the atmospheric pressure (see Figure 1). In SI units: 1.01 x 10^5 Pa.

You will find an equation list as well as the constants which you should memorize here: www.goldstandard-mcat.com/physics-equation-lists/

[h99h20baby]

thank you

[hulk475390]

You specifically list Bernouilli's Equation under 'do not memorize, but know how to use' and then require us to know it on this test. I understand the concept, but don't have it memorized. Should I? I am struggling to get all the required information and to add non-essentials seems like a waste of time.

[nedaa.asba6809]

Bernouilli's Equation is not necessary to solve this problem. One of the equations on your list to memorize is that the change of pressure is equal to rho-g-h (ie density times gravity times height/depth). This is the equation that was used to solve this problem.

[Guest]

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