I don't know if this should be in the spam section or not - but if a mod wants they can close itas soon as someone helps me with this problem.
You see, I got a physics test tomorrow, and out of my 3 courses this semester it i by far my weakest subject (because I never took it i grade11), and I got the last test on the motion section of it all tomorrow morning. So I've been doing review questions, and have gotten all of them right so far, but this one has me stumped:
"As a pilot comes out of a dive in a circular arc, she experiences an upward acceleration of 9.0g's.
a) If the pilot's mass is 60kg, what is the magnitude of the force applied to her by her seat at the bottom of the arc?
If the speed of the plane i 330km/h, wat is the radius of the plane's arc?"
I'm assuming I could get part b), but part a) seems awkward. I'm trying to use the forumlas in my notes, but I can't seem to get the right answer, which is:
5.9 x 10^3 Newtons.
If anyone can find it, please post hw you solved it out, please and thank you. If you need any extra info on what exactly we learned, just ask. One thing I don't know is which particular force they are asking for in the question.
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One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
if you take force=mass*acceleration, i believe all you would do is break down the acceleration into it's two component vectors and apply the mass to the acceleration in the correct direction. you should have an equation for determining component vectors, just a bunch of geometry really. If i am way off and you tried that and it didnt work, ill fall bck on i took physics for engineers over 3 years ago, and havent opened the book in as long.
Rekab, in the question (part a) it states that they areat the bottom of the arc, and therefore there are no components. God help me if we're working on an angle of the arc and have to use components, god help us all.
Anyways in my calc. class (the period right before physics), I asked a friend and got a quick explanation, but I forgot, and guess what! It was on th test, but I managed to do the equation manipulations to get part-way there.
I had a major goof up on another part though. It had to do with orbits and stuff, and one question gave us only the mass and the radius of the sun to the planet (Saturn), basically the radius of the circular orbit. The first part of the question asked to find the amount of time it would take to complete one orbit, or in other words - 1 period. So I managed to find the orbital speed of Saturn, and was trying to figure out how to find the distance travelled in the orbit. Then it popped i my head, find the circumference using the radius! Duh!
Oh wait.. after having to know a page full of physics equations and not having used the circumference formula for 4 years, I completely forgot what it was! And ACTUALLY said circumference = 4 x Pi x r^2
Yes, "Four Pi 'r' Squared", not the simple "Two Pi 'r' ". -.-
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One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
I don't believe I've taken this, but I'll have a go at it. You can get the magnitude by applying Newton's second law stating that F=ma. You have the acceleration in g's, so the use of the question saying "bottom of the arc" is that you can then take that as your reference level and take the gravitational potential energy to be equal to 0 at said level. I may be wrong though.
I don't know about the second, since I have no clue about the formula concerning it.
g is the acceleration due to gravity... so for the F=ma the "ma" would just be the mass of the person times 9.8 times 9
then for the second part, since it's an arc wouldn't centripetal force be involved?
assuming that, (which might be wrong..)
(from wikipedia since i can't ever remember these damn equations) The centripetal force is F = mxa = rxmxω 2 = r−1xmxv 2.
(just look on wiki if you can't read those formulas the forum formatting sort of owned it)
so using that last you can get 5292N= (60kg) x (91.67m/s)^2 <-----(converted 330km/hr to 91.67m/s)
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``````````````````````````````````````r
so then r would be 95m?
i don't know that's my crack at it and probably exposes how bad i am at physics
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they'll never see me coming.. life is a sequence of tragedies, inconsistent only by fleeting, elusive moments of pleasure,
serving only to ensure absolute vulnerability to the pain of their inevitable absence.
"As a pilot comes out of a dive in a circular arc, she experiences an upward acceleration of 9.0g's.
a) If the pilot's mass is 60kg, what is the magnitude of the force applied to her by her seat at the bottom of the arc?
This might be it, though the question is worded strange if so.
Since the pilot is at the bottom of the arc, there's only one vector, and it's straight up. If she accelerates upwards with 9 g's, then the seat is pushing at her with that exact force. Add to that the Earth's pull, and the seat as to press with 1 additional g to make up for the gravitational pull down, which adds up to 10 g's.
60*9,81*10=5886=5,9*10^3 N
Quote from "Killer-Swift" »
If the speed of the plane i 330km/h, wat is the radius of the plane's arc?"
Ok, so we have the centripetal acceleration from the previouse example. Using the forumla
a=(v^2)/r, we can eaasily figure out the radius of the loop, by first converting the speed to m/s.
9*9,81=(91,7^2)/r
r=95,2
Which however seems awfully small. I'm not so sure about that last part, half a year since I did this. Hope it helps though
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Okay the first part you did Phrozen seems to be right, as they do tend to round just for "Sig Digs", so what you did does go to 5.9 x 10^3 N, I never really though of it that way before. Theway we were taught to do it in our class (looking at notes) i to do a lot of formula manipulation, so we get Fn = Fc + Fg or something (basically stating that your force of normal is equal to Centripetal Force plus Forge of Gravity). Centripetal Force is basically the name of the force we use instead of Net Force (Fnet), and is ALWAYS pointed in the same direction as Centripetal Acceleration (pointing at a 90 degree angle to the instantaneous velocity, and directly at the centre of the radius).
An yeah PD, the second half seemed easy, but I couldn't do i because I needed the force from te first part. =/
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One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
oops forgot the normal earth g for the first part ><
yes gj phrozen
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they'll never see me coming.. life is a sequence of tragedies, inconsistent only by fleeting, elusive moments of pleasure,
serving only to ensure absolute vulnerability to the pain of their inevitable absence.
Well, looks like I'm out-matched when it comes to physics in this group...not unlike most other places cause I hate physics....marine biology questions anyone?
Well, looks like I'm out-matched when it comes to physics in this group...not unlike most other places cause I hate physics....marine biology questions anyone?
what respiratory system does a jellyfish, fish, frog, and earthworm have in common?
it was a question on my test today. i said they all require a moist membrane for O2 diffusion. but im not sure about the frog since it has a 3 chamber heart. or the fish because it intakes o2 from water, but gills are exposed to water...sooo. i know an earthworm and blah....it was a hard question
@killer
its only been 1 semester since i took physics, but ive already forgotten lol. all i know is resistance is not futile, its volts divided by amperes (get it?). n e way...that force stuff was hard, i think i got like a 54 on the exam...but thankfully we get to drop our lowest exam score soooo yay!!!
ah well...good luck on further exams mon ami
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Remember the String of Ears
"to the worm in horseradish, the world is horseradish."
As I said, I had the test today, so thanks everyone for the wishes. Haha, I think I actually did fairly decently. But my teacher likes to give us theoretical questions where we're usually missing lots of information or possibly even all of it and asks us to solve it in a specefic way, its damn hard sometimes, lol.
Quote from "Equinox" »
What happened to the good old Fnet = ma aka Fc = mv^2/r
This seems like a pretty simple problem...
Because in this problem we're not given speed, nor radius. Therefore we can;t use that standard Fc equation. If I pulled out my notes I could sort-of show you how to find it another way. but regardless, I think PhrozenDragon had it the right way =P. I feel stupid for forgetting to add on that last "g", I did what blood-doll had done and got 5292 instead of 5898 or something like that. =/
OH! We're done Motion physics now (motion took up all of the first term), we just started Light and Waves, and afetr that we'll be doing Quantum Mechanics. And thankfully I've got a good background with Quantum mechanics thanks to 4U Chem' class.
Thanks Apples, I used to like doing force equations, because when I first learned it (where I had to teach myself the whole 3U physics course in one day ><) it was really simple stuff like Eg = mgh and Fg = mg. Bah, but doing so much motion for so long, I'm starting to hate it lol. I'm really hoping we get to the electricity unit though, ebcause I need to know that stuff for what I plan to go into Uni for.
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One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
not sure if it was a valid way but i did use that f = (mv^2)/r way and got the same answer as phrozen for the second part
(the one phrozen used is just a derivation i think?)
anyway hope you did well
edit also grats on being past that part (never liked the centripetal or torque stuff either)
light and waves i think is conceptually easier to understand, and quantum stuff is either really interesting or just memorization depending..:) gl on them as well
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they'll never see me coming.. life is a sequence of tragedies, inconsistent only by fleeting, elusive moments of pleasure,
serving only to ensure absolute vulnerability to the pain of their inevitable absence.
What happened to the good old Fnet = ma aka Fc = mv^2/r
Quote from "blood-doll" »
not sure if it was a valid way but i did use that f = (mv^2)/r way and got the same answer as phrozen for the second part
(the one phrozen used is just a derivation i think?)
Yeah I used the same. Mass was both sides of the equation, so there was no need to keep it in there.
Quote from "Killer-Swift" »
OH! We're done Motion physics now (motion took up all of the first term), we just started Light and Waves, and afetr that we'll be doing Quantum Mechanics. And thankfully I've got a good background with Quantum mechanics thanks to 4U Chem' class.
Light, or rather waves, is really frustrating at times to grasp I think.
Quote from "Killer-Swift" »
Thanks Apples, I used to like doing force equations, because when I first learned it (where I had to teach myself the whole 3U physics course in one day ><) it was really simple stuff like Eg = mgh and Fg = mg. Bah, but doing so much motion for so long, I'm starting to hate it lol. I'm really hoping we get to the electricity unit though, ebcause I need to know that stuff for what I plan to go into Uni for.
And electricity is pretty fun, though I think I'm the only one in my entire class who actually liked that part
PlugY for Diablo II allows you to reset skills and stats, transfer items between characters in singleplayer, obtain all ladder runewords and do all Uberquests while offline. It is the only way to do all of the above. Please use it.
Supporting big shoulderpads and flashy armor since 2004.
Yeah I know, but thats for the second part, which I could do if I knew the answer for the first part (which technically I do know thanks to the answer sheet in the back of the book), but I prefer to only do the second part of the question until after I do the first, etc. The question I was having an issue was with the first one, but thanks everyone for the help.
Now next up! A calc quiz on monday and a biology quiz on tuesday,yay! [/sarcasm]
I could imagine how waves can be confusing, we just started it and it seems like such a touchy subject, but its something new and it may be fun. I really do hope we get to the electricity unit, mainly because thats what I took physics for!
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One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
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You see, I got a physics test tomorrow, and out of my 3 courses this semester it i by far my weakest subject (because I never took it i grade11), and I got the last test on the motion section of it all tomorrow morning. So I've been doing review questions, and have gotten all of them right so far, but this one has me stumped:
"As a pilot comes out of a dive in a circular arc, she experiences an upward acceleration of 9.0g's.
a) If the pilot's mass is 60kg, what is the magnitude of the force applied to her by her seat at the bottom of the arc?
If the speed of the plane i 330km/h, wat is the radius of the plane's arc?"
I'm assuming I could get part b), but part a) seems awkward. I'm trying to use the forumlas in my notes, but I can't seem to get the right answer, which is:
5.9 x 10^3 Newtons.
If anyone can find it, please post hw you solved it out, please and thank you. If you need any extra info on what exactly we learned, just ask. One thing I don't know is which particular force they are asking for in the question.
One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
That stuff makes me head spin just looking at it.
CyberPunk RP Nexus
Anyways in my calc. class (the period right before physics), I asked a friend and got a quick explanation, but I forgot, and guess what! It was on th test, but I managed to do the equation manipulations to get part-way there.
I had a major goof up on another part though. It had to do with orbits and stuff, and one question gave us only the mass and the radius of the sun to the planet (Saturn), basically the radius of the circular orbit. The first part of the question asked to find the amount of time it would take to complete one orbit, or in other words - 1 period. So I managed to find the orbital speed of Saturn, and was trying to figure out how to find the distance travelled in the orbit. Then it popped i my head, find the circumference using the radius! Duh!
Oh wait.. after having to know a page full of physics equations and not having used the circumference formula for 4 years, I completely forgot what it was! And ACTUALLY said circumference = 4 x Pi x r^2
Yes, "Four Pi 'r' Squared", not the simple "Two Pi 'r' ". -.-
One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
I don't know about the second, since I have no clue about the formula concerning it.
Rise and rise again, until lambs become lions
then for the second part, since it's an arc wouldn't centripetal force be involved?
assuming that, (which might be wrong..)
(from wikipedia since i can't ever remember these damn equations) The centripetal force is F = mxa = rxmxω 2 = r−1xmxv 2.
(just look on wiki if you can't read those formulas the forum formatting sort of owned it)
so using that last you can get 5292N= (60kg) x (91.67m/s)^2 <-----(converted 330km/hr to 91.67m/s)
```````````````````````````````_________________
``````````````````````````````````````r
so then r would be 95m?
i don't know that's my crack at it and probably exposes how bad i am at physics
they'll never see me coming..
life is a sequence of tragedies, inconsistent only by fleeting, elusive moments of pleasure,
serving only to ensure absolute vulnerability to the pain of their inevitable absence.
Since the pilot is at the bottom of the arc, there's only one vector, and it's straight up. If she accelerates upwards with 9 g's, then the seat is pushing at her with that exact force. Add to that the Earth's pull, and the seat as to press with 1 additional g to make up for the gravitational pull down, which adds up to 10 g's.
60*9,81*10=5886=5,9*10^3 N
Ok, so we have the centripetal acceleration from the previouse example. Using the forumla
a=(v^2)/r, we can eaasily figure out the radius of the loop, by first converting the speed to m/s.
9*9,81=(91,7^2)/r
r=95,2
Which however seems awfully small. I'm not so sure about that last part, half a year since I did this. Hope it helps though
An yeah PD, the second half seemed easy, but I couldn't do i because I needed the force from te first part. =/
One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
yes gj phrozen
they'll never see me coming..
life is a sequence of tragedies, inconsistent only by fleeting, elusive moments of pleasure,
serving only to ensure absolute vulnerability to the pain of their inevitable absence.
This seems like a pretty simple problem...
it was a question on my test today. i said they all require a moist membrane for O2 diffusion. but im not sure about the frog since it has a 3 chamber heart. or the fish because it intakes o2 from water, but gills are exposed to water...sooo. i know an earthworm and blah....it was a hard question
@killer
its only been 1 semester since i took physics, but ive already forgotten lol. all i know is resistance is not futile, its volts divided by amperes (get it?). n e way...that force stuff was hard, i think i got like a 54 on the exam...but thankfully we get to drop our lowest exam score soooo yay!!!
ah well...good luck on further exams mon ami
"to the worm in horseradish, the world is horseradish."
Because in this problem we're not given speed, nor radius. Therefore we can;t use that standard Fc equation. If I pulled out my notes I could sort-of show you how to find it another way. but regardless, I think PhrozenDragon had it the right way =P. I feel stupid for forgetting to add on that last "g", I did what blood-doll had done and got 5292 instead of 5898 or something like that. =/
OH! We're done Motion physics now (motion took up all of the first term), we just started Light and Waves, and afetr that we'll be doing Quantum Mechanics. And thankfully I've got a good background with Quantum mechanics thanks to 4U Chem' class.
Thanks Apples, I used to like doing force equations, because when I first learned it (where I had to teach myself the whole 3U physics course in one day ><) it was really simple stuff like Eg = mgh and Fg = mg. Bah, but doing so much motion for so long, I'm starting to hate it lol. I'm really hoping we get to the electricity unit though, ebcause I need to know that stuff for what I plan to go into Uni for.
One becomes strong when they are fighting to protect someone close to them... - Shiro Haku
(the one phrozen used is just a derivation i think?)
anyway hope you did well
edit also grats on being past that part (never liked the centripetal or torque stuff either)
light and waves i think is conceptually easier to understand, and quantum stuff is either really interesting or just memorization depending..:) gl on them as well
they'll never see me coming..
life is a sequence of tragedies, inconsistent only by fleeting, elusive moments of pleasure,
serving only to ensure absolute vulnerability to the pain of their inevitable absence.
Light, or rather waves, is really frustrating at times to grasp I think.
And electricity is pretty fun, though I think I'm the only one in my entire class who actually liked that part
Now next up! A calc quiz on monday and a biology quiz on tuesday,yay! [/sarcasm]
I could imagine how waves can be confusing, we just started it and it seems like such a touchy subject, but its something new and it may be fun. I really do hope we get to the electricity unit, mainly because thats what I took physics for!
One becomes strong when they are fighting to protect someone close to them... - Shiro Haku