physics

[premed1001]

Answered
question

answer

this doesn't make any sense to me.
i am imagining a balloon filled with air for the mass, since it has a low density.
OK so if the container is jerked upward, wont the mass initially want to remain in its location due to its inertia, reducing tension, as the distance between the mass and the bottom of the container decreases????

can someone explain please?

thanks

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[premed1001]

Answered
here is another one:
figure

questions

answers

ok i understad 562 because it is simply atmospheric pressure plus pgh

i dont understand 561. why is just pgh and not atmospheric pressure? does the top of the siphon not experience atmospheric pressure due to the water in the tank, as well?

TIA!

 

[premed1001]

Bump

 

[premed1001]

anyone?

 

[4563728]

Found an old link for you...http://forums.studentdoctor.net/threads/examkracker-fluid-pressure-question.891435/

Good luck!

 

[Dentsss]

Good to know

 

[Blueprint MCAT Tutor]

That's a really great, interesting first question. Response here:

http://forums.studentdoctor.net/threads/specific-science-questions.1053558/

Scroll down to the bottom.

 

[premed1001]

That's a really great, interesting first question. Response here:

http://forums.studentdoctor.net/threads/specific-science-questions.1053558/

Scroll down to the bottom.

Wonderful! Thank you so much! I never considered the waters inertia lol

 

[premed1001]

Unanswered

answer

ok so,
a is incorrect from pv=nrt T goes down so P goes down as well
B is incorrect from 1/2 rho v^2 and from rho g h if rho goes down so does P
i thought d was incorrect from 1/2 rho v^2 if v goes down then wouldnt P as well?
i thought c was correct from P=F/A A goes down, shouldnt P go up?

 

[lexw]

my thought process (not 100% sure its right but ill give it a shot)

a) youre right, T decrease causes P to go down
b) same as you where a decrease in density means a decrease in viscosity increasing flow rate. poiseuilles principle (this one im not 100% on)
c) decrease in area with the same flow rate means increase in velocity Q=Av (continuity) increase v in bernoullis equation means P decrease.
d) youre right that since v goes down it causes the term 1/2rho v^2 to decrease, but according to bernoullis equation, to keep k constant at a specific temperature something needs to change for a balance, thus P increases.