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#1
This is really easy stuff, but my mind is completely blank for some reason, and I need to get it done by tomorrow.

A self-propelled balloon car goes 4.3 meters. It took 2.35 seconds to cover 3 meters. It's mass is 7.9g.

So here's what I need to find out:

Car's average speed: .783m/s, correct? time/distance; 2.35/3?
Car's weight in Newtons and mass in kilograms: .07742 N and .0079 kg, right?
Car's final velocity at the end of the 2.35 seconds: No idea. Don't I need to find the acceleration rate first though?
Car's Kinetic Energy: 1/2mv^2, so .00395? X_X
Car's final momentum: .0061857 kg m/s or whatever the damn unit is?
Total work done by balloon: ?
Potential Energy of the balloon before the start: =KE?
Total power balloon produced: ?


You guys are smart, please help me!

<33

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#6
Quote by Zuka
I plan on getting by with my looks.


Same, but my physics teachers a dood.

What has this country come to?
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#8
Is this just an equation you were given or did you actually do this expierment.


If you did....your a noob. Mine went 12 meters
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#10
Ew. Don't remind me of physics. I have a final tomorrow in that class that I'm going to fail ><
#11
Quote by alienboy18241
Is this just an equation you were given or did you actually do this expierment.


If you did....your a noob. Mine went 12 meters


We did an experiment. We had extremely limited rescources, and this is what we got on our first try.
Quote by cubedeathk

No my friends Dinosaurs walked this earth with Man.


#13
Quote by QuiteTheFellow
Same, but my physics teachers a dood.

What has this country come to?

Together, us beautiful people will crush on through, forging a path unworthy of gazing upon us.

/endpompousness
#14
Quote by Zuka
Together, us beautiful people will crush on through, forging a path unworthy of gazing upon us.

/endpompousness


Yeah, thanks. But I need to get through school first.

So until then, NERDS OF THE PIT, UNITE! and help me with my homework
Quote by cubedeathk

No my friends Dinosaurs walked this earth with Man.


#15
Quote by QuiteTheFellow
This is really easy stuff, but my mind is completely blank for some reason, and I need to get it done by tomorrow.

A self-propelled balloon car goes 4.3 meters. It took 2.35 seconds to cover 3 meters. It's mass is 7.9g.

So here's what I need to find out:

Car's final velocity at the end of the 2.35 seconds: No idea. Don't I need to find the acceleration rate first though? x=x(i)+v(i)t+at^2, solve for a. then v=v(i)+at. Maybe try another kinematics equation, if those don't work
Total work done by balloon: ? W=Fx
Potential Energy of the balloon before the start: =KE? Ug=mgh is potential energy
Total power balloon produced: ? P=W/t

x=final position
x(i)=initial position
v(i)=initial velocity
v=final velocity
t=time
a=acceleration
W=work
Ug=Potential Energy
m=mass
g=acceleration due to gravity
h=height
P=Power


I don't feel like plugging in all the numbers, but that should help a little, those are the right equations bolded I believe. Unfortunately my AP physics class isn't really advanced where we would use the calculus methods with derivatives and whatnot, so we just kind of have basic equations and whatnot. If you're in a higher level thing maybe that doesn't help.
Last edited by SickMetal at Jan 24, 2007,
#16
It's pathetic I can't answer this considering we covered this several chapters ago
#17
d=vit+(1/2at2)

the second 2 is an exponent.
that might help
cause the initial velocity(vi) =0
therefore you can cross that out... divide distance by tsquared and multiply by 2
voila
acceleration
thatshouldwork.
#19
Quote by SickMetal
I don't feel like plugging in all the numbers, but that should help a little, those are the right equations bolded I believe.



Dude, thank you so much!



Edit: Position is the same thing as distance, right?
Quote by cubedeathk

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Last edited by QuiteTheFellow at Jan 24, 2007,
#20
Physics?





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Saxo-Walrus

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#22
Quote by QuiteTheFellow
Dude, thank you so much!



Edit: Position is the same thing as distance, right?

Yeah, basically. It's the distance from wherever you want to call zero (You could make it easier on yourself by defining the initial position as zero so it's not as confusing, lol).

Hope that helps.

I just got my ass busted by an AP physics midterm the other day so I'm not going too crazy here lol, those are all equations and stuff, if you need more help you can ask.
#23
^(to the dude with the elephant)

One more question, how do I find force? =(
Quote by cubedeathk

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#24
Quote by fallenangel20
Physics?




ROFL.

What you can do is use a conservation of energy principle.

Ei=Ef

So, the potential energy of this thing at rest on top of the ledge or whatever would be equal to the potential energy when it's on the spring.

So,

Ug=Us
mgh=kx^2
Solve for x

^^F=ma. Newton's laws and whatnot.
#25
I'm actually interested in those raptor questions.

I'm sure it's easy, but it kills me how awesome those questions are.

EDIT: The whole "The raptors run a 10m/s, and they know no fear" part is funny as hell, as well.

I wish I had floor plan as well.
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Last edited by fallenangel20 at Jan 24, 2007,
#26
Average velocity = 1.2765
Weight + Mass = .07742 N , .0079 kg

This question doesn't give all the right information for final velocity and potential energy(there's no height so the formula PE=mgh doesnt apply) (and there's no initial or final velocity for the 2.35 seconds of travel)

Work = .03397 Joules
Power = .425531 Watts
#27
Quote by XMetallica73X
Average velocity = 1.2765
Weight + Mass = .07742 N , .0079 kg

This question doesn't give all the right information for final velocity and potential energy(there's no height so the formula PE=mgh doesnt apply) (and there's no initial or final velocity for the 2.35 seconds of travel)

Work = .03397 Joules
Power = .425531 Watts


Thanks!

The initial velocity is given as 0, final velocity isn't given.

As for the PE formula, I think I need to find the elastic potential energy, not gravitational. Don't remember that formula though =(

Also, how did you find the average velocity? My brain needs a refresher.
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#28
Quote by fallenangel20



that is AWESOME

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#29
Quote by fallenangel20
I'm actually interested in those raptor questions.

I'm sure it's easy, but it kills me how awesome those questions are.

EDIT: The whole "The raptors run a 10m/s, and they know no fear" part is funny as hell, as well.

I wish I had floor plan as well.


no matter what they would get you faster seeing as you only run 6 m/s and the slowest raptor goes 10 m/s, plus it would take the other two raptos 4.5 seconds to get to the center which is way enoguh time to regroup and get you no matter which way nyou ran
#30
Quote by XMetallica73X
no matter what they would get you faster seeing as you only run 6 m/s and the slowest raptor goes 10 m/s, plus it would take the other two raptos 4.5 seconds to get to the center which is way enoguh time to regroup and get you no matter which way nyou ran


True, but also, depending on the terrain, it could take some time.

But since they don't give a certain land type, I guess we can just use plain, flat, dirt area.

I love the last question, though. Just the idea to make a floorplan to escape, and taking into account they adapt to the doors and all, it's genius.
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#31
Quote by fallenangel20





1. Find when the position of you and the raptor are the same.

Find how far the velociraptor went in the time it took him to reach top speed.

v=v(i)+at^2
25 m/s=0 +(4m/s^2)(t^2)
(25/4)^(1/2)=t
t=2.5

d=d(i)+v(i)t+at^2
Plug it in.

Then find out how far you went in 2.5 seconds.

Then set the position formula equation equal to itself with one side being the guy (with all the data at their values at 2.5)and one side being the raptor(again, at 2.5s) and solve for t. Then add that t to 2.5 and plug it in to find how far you went.
2. I'm sure that's pretty easy but I don't have the time/patience to look at it now, lol.
3. Lol, you can figure that out.

To the other dude, the formula for the potential energy of a spring is Us=kx^2 with k being the spring constant and x being the distance that the elastic thing is compressed by whatever's pushed into it.
#32
Damn.... this makes me want to know physics....I've always found it interesting, but I've enver had the chance to learn. I'm in the only 10th grade....Biology....meh. IT's okay, but the teacher's too stubborn, she ALWAYS has to be right, and biology just isn't my thing.
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#33
Quote by QuiteTheFellow
Thanks!

The initial velocity is given as 0, final velocity isn't given.

As for the PE formula, I think I need to find the elastic potential energy, not gravitational. Don't remember that formula though =(

Also, how did you find the average velocity? My brain needs a refresher.


Vavg=d/t

ok so for the other question you use D=1/2(a)(t)^2 4.3=1/2(a)(2.35)^2
4.3=2.761(a) A=1.557 the you use Vf=Vi + (a)(t) Vf=0 + (1.557)(2.35)

Vf = 3.65 Vf is final velocity by the way
#34
Yeah dude, I'll be honest, I thought 9th grade honors bio and 10th grade honors Chemistry sucked, but I'm in 11th grade AP Physics and I actually like it. I'd probably appreciate the other two more now because they always just teach you the easy basics, and the fact is that the other two have a lot of things that come directly from physics, so the subjects aren't really that different from each other, it's all branching off the same thing.
#35
I was going to take physics next year, but I am taking Pre-calc, and didn't really want two math courses (pretty much) so I decided to take pshycology instead, which should be awesome.
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#36
Quote by XMetallica73X
Vavg=d/t

ok so for the other question you use D=1/2(a)(t)^2 4.3=1/2(a)(2.35)^2
4.3=2.761(a) A=1.557 the you use Vf=Vi + (a)(t) Vf=0 + (1.557)(2.35)

Vf = 3.65 Vf is final velocity by the way


For the Vf I got 2.557m/s =(

I did:

a=2d/t^2
a=6/5.52
a=1.09
Then:
[sqr() means square root]

Vf=sqr(2ad)
Vf=sqr(6a)
Vf=sqr(6*1.09)
Vf=sqr(6.54)
Vf=2.557

What did I do wrong? =(

Also, whats the formula for force?
Quote by cubedeathk

No my friends Dinosaurs walked this earth with Man.


#38
F=ma
Force=mass • acceleration

Sickmetal, are you taking Physics B? I'm in Pre-AP Physics this year, and I'm taking AP Physics C next year.
#39
Yeah, I'm in Physics B. Definitely gonna take C next year. I'm taking Calculus AB this year so the math part shouldn't be too tough, I just want to see how they correspond to each other.

To the dude with the Pre-Calc and the not taking Physics...the math part of Physics isn't very difficult as long as you're not doing courses that involve derivatives and integration and stuff (which you shouldn't be if it's the first time you take physics, like me), it's basically a Science course that uses some math skills, nothing crazily difficult.
#40
Quote by XMetallica73X
Average velocity = 1.2765
Weight + Mass = .07742 N , .0079 kg

This question doesn't give all the right information for final velocity and potential energy(there's no height so the formula PE=mgh doesnt apply) (and there's no initial or final velocity for the 2.35 seconds of travel)

Work = .03397 Joules
Power = .425531 Watts


PE=KE = 1/2 mv^2 physics noob
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