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Mathematics 17 Online
OpenStudy (anonymous):

@Outkast3r09

OpenStudy (anonymous):

i see boxes =P

OpenStudy (anonymous):

Mechanical energy vertical displacent energy

OpenStudy (anonymous):

umm? ok question?

OpenStudy (anonymous):

I've been up since 5 am :'( can't think anymore. what happens to energy in this situation?

OpenStudy (anonymous):

now we have potential energy correct?

OpenStudy (anonymous):

V?

OpenStudy (anonymous):

mgh?

OpenStudy (anonymous):

E= U + K

OpenStudy (anonymous):

\[\frac 12 mv^2\]

OpenStudy (anonymous):

C=Q/V?

OpenStudy (anonymous):

what do you mean?

OpenStudy (anonymous):

what happens to the energy in terms of mechanics?

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

well lets see it starts with a potential energy and no kinetic

OpenStudy (anonymous):

we're only looking at it before and after it finished moving, so: no K I think

OpenStudy (anonymous):

so what happened to the energy you are trying to ask?

OpenStudy (anonymous):

since you end up with no kinetic or potential?

OpenStudy (anonymous):

oh it's lifting the object

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

sorry

OpenStudy (anonymous):

the capacitor i'm assuming is using the energy to do work , and potential

OpenStudy (anonymous):

sounds right

OpenStudy (anonymous):

so C=Q/V voltage from where? battery? outlet?

OpenStudy (anonymous):

yes battery

OpenStudy (anonymous):

where rae you getting it? lol outlet and battery are different lol

OpenStudy (anonymous):

alright

OpenStudy (anonymous):

I guess I have to relate \[C=QV\] to \[U=\frac 12 CV^2\] to \[mgh\] what are we solving for? the displacement?

OpenStudy (anonymous):

we know V \[mgh=\frac 12 CV^2\] we know mg and V

OpenStudy (anonymous):

how can we get C? where is work? LOL

OpenStudy (anonymous):

what about work?

OpenStudy (anonymous):

\[W=\int F\cdot dr\] or E dr

OpenStudy (anonymous):

http://en.wikipedia.org/wiki/Work_%28electrical%29

OpenStudy (anonymous):

http://en.wikipedia.org/wiki/Work_%28electrical%29 work and potential energy!!!!

OpenStudy (anonymous):

would work be electrical in this case though since it's mechanical work?

OpenStudy (anonymous):

sure

OpenStudy (anonymous):

is that yes or no lol

OpenStudy (anonymous):

yes?

OpenStudy (anonymous):

potential energy

OpenStudy (anonymous):

So what is the actual question... i haven't actually gotten a question.. I've gotten 2 formulas and a procedure it sounds like lol

OpenStudy (anonymous):

also dr = h

OpenStudy (anonymous):

;)

OpenStudy (anonymous):

W=Fd=Fh \[mgh+Fh=

OpenStudy (anonymous):

\[h(mg+F)\]?

OpenStudy (anonymous):

we dont have to integrate i'm assuming

OpenStudy (anonymous):

no it's straight up

OpenStudy (anonymous):

alright

OpenStudy (anonymous):

now we need the work done

OpenStudy (anonymous):

?

OpenStudy (anonymous):

yes isn't that what it's asking lol

OpenStudy (anonymous):

so you're lifting the mass meaning there is work being done = energy being used to lift it

OpenStudy (anonymous):

I'm tired dude.... ok so we used up E

OpenStudy (anonymous):

E= U+0

OpenStudy (anonymous):

ok so E is actually your capacitor right?

OpenStudy (anonymous):

I hope so....let's say it is

OpenStudy (anonymous):

Alright so E is equation 24-8 in page you showed me

OpenStudy (anonymous):

since \[E_1=E_2\] \[E_1=mgh+\frac{1}{2}mv^2+U_c\]

OpenStudy (anonymous):

\[mg(0)+\frac{1}{2}m(0^2)+U_c\]

OpenStudy (anonymous):

so all energy is coming from the capacitor

OpenStudy (anonymous):

now the other side you have \[mgh+\frac{1}{2}mv^2+W_{app}+W_d\]i'm assuming drag will be really low so it's not taken into account

OpenStudy (anonymous):

what's W app? and W d?

OpenStudy (anonymous):

but since we're looking at it at rest in two places you have \[mgh+0+Fh\] \[U_c=mgh+Fh=(mg+F)h\]

OpenStudy (anonymous):

this is what i'm thinking but i'm only like 50% certain lol

OpenStudy (anonymous):

if it isn't that much don't worry about it

OpenStudy (anonymous):

\[F=ma\] \[(mg+ma)h=(m(g+a))h\]

OpenStudy (anonymous):

\[\frac{U_c}{m(g+a)}=h\] maybe!?!?!?! lol

OpenStudy (anonymous):

W_d is work done by the drag force... which is going to be nothing probably since the velocity will be minimal

OpenStudy (anonymous):

that's sort of a toughie question... we haven't gotten to capacitors and such yet

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