To Smart people (and to future Chemists & Mathematicians)

[No reply]

yep, although if you do simple free fall with the given values of 160m and 24m/s, then the equation he provided for the trajectory doesnt even come close to the actual situation

If no equation was given, I would agree with you.

[TOloseGT]

Yeah I did make a small typo but I corrected it a while ago though. :/

And yes the distance traveled is the length of that arc as in my pic of paint I posted. It should be longer than the distance of the pythagorean theorem since it's not straight if u know what i mean.

then that booklet is not giving u enough information. are you positive it isn't asking for the x distance?

if it is x distance ( as i am led to believe because of the question):

first, figure out time (t):
use this eqn--> change in Y = velocity initial - (0.5)(acceleration of gravity)(t^2)
-160 = 0 - (0.5)(9.8 )(t^2)
t ~= 5.71 s

then distance of x = velocity of x * time
x = 24 m/s * 5.71 s
x = 137.04 m

see if that answer's right

EDIT: they gave u the trajectory equation to mislead you.

[NuclearSilo]

The bird hits ground at the time y equal 10m because they dont have the same origin.

untitled.JPG (16.22 KiB) Viewed 2153 times

Btw, if the bird is at 160m height, then the solution is 80m

Come on TOloseGT, he is talking about x not t
it's y=160-x²/40 not y=160-t²/40

[No reply]

1. the task doesn't say anything about constant acceleration, so we have to rely on the formula.

2. y(0) = 160 (as stated)

3. Distance traveled = x.

Btw, if the bird is at 160m height, then the solution is 80m

Been said , props for the nice graph though.

[TOloseGT]

Come on TOloseGT, he is talking about x not t
it's y=160-x²/40 not y=160-t²/40

i know, i figured out t to figure out x.

the question even says "x is the horizontal distance traveled in meters"

[ThiefzV2]

The bird hits ground at the time y equal 10m because they dont have the same origin.

untitled.JPG

Btw, if the bird is at 160m height, then the solution is 80m

Come on TOloseGT, he is talking about x not t
it's y=160-x²/40 not y=160-t²/40

Nuclear, the bird was dropped at 160, there was a very minor typo that I fixed 10 minutes after I posted. Sorry about that. And the answer key say it's 186m.

[No reply]

thought it meant the horizontal distance at first.
This gives it a whole new meaning, have you learned integration yet?

[ThiefzV2]

You got the 2nd one right but not the first one (not even close) ... hmmmm what could be the reason?

Oh snaps, you got the answer? I think I got it right, unless my mistake has something to do with sig figs and units. T.T

Yeah, it was 19M. But can you figure out what you did wrong in the chemical eq?

[ThiefzV2]

BTW, I have a question. Why are you guys adding a time variable? Time is not a factor... they just want to know the distance traveled by the prey when it is dropped at 160m until the time it hits the ground. I don't see where the time t comes into play. Because the prey is dropped while in motion, it has a parabolic path so i think the 24m/s is there just to let you know it isn't a free fall and the path of the drap is parabolic like the one i drew in Paint:





this isnt a free fall question.


EDIT: have anyone figure out how to arrive at the solution? nuclear, no reply, tolosegt, vindicator, etc?

[Vindicator]

it is a free fall question because the only force acting on the object is gravity as long as you neglect air friction, which is what free fall is, however this is asking something I have never seen asked before...its generally find the distance x traveled by the time it hits the ground....if your trying to find the length of the arc, i have no idea how to arrive there yet.

[NuclearSilo]

sleep time, see u

Just 2 notes:
-if u use trajectory eq, u dont need velocity
-if u use velocity and free fall, u dont need trajactory eq

[ThiefzV2]

it is a free fall question because the only force acting on the object is gravity as long as you neglect air friction, which is what free fall is, however this is asking something I have never seen asked before...its generally find the distance x traveled by the time it hits the ground....if your trying to find the length of the arc, i have no idea how to arrive there yet.

yes the length of that arc is the distance travel by the prey. that's what we are trying to figure out lol. i dont believe time has nothing to do with it since the equation don't use time, so I don't see why you guys would introduce it to your solutions.

[No reply]

You're supposed to use the formula somehow, and they clearly asks for the "length of the graph" (i.e. distance traveled). Let's assume the acceleration is constant (which is far from the truth), then the distance would be sqrt(80^2 + 160^2)= 178. The graph is not a straight line though, and the only solution seems to be integration.

[Kazaxat]

He doesn't claim to be intelligent, he is. You on the other hand appear to be threatened by his apparent intelligence. If you want to prove you're better at math than silo, beat him at his own game, rather than spewing verbal fodder such as; "blah,blah".

lol i never claim im good at math. im a white kid and white people suck at math. nuclear is asian.

but what i dont like are people that pretend to act intelligent and call other people dumb. and lol nuclearsilo cant even solve a simply prey problem. go figure lol

[ThiefzV2]

You're supposed to use the formula somehow, and they clearly asks for the "length of the graph" (i.e. distance traveled). Let's assume the acceleration is constant (which is far from the truth), then the distance would be sqrt(80^2 + 160^2)= 178. The graph is not a straight line though, and the only solution seems to be integration.

so what do i plug into what to get the soln?

[Vindicator]

WOW! I just wana slap the shit out of myself for being so stupid. I got it. The problem is that the equation does not provide a circle for which to use theta = arc / radius or any other geometric / trigonometric equation. So the answer is in calculus.

You can use Reaimman sums (sp?) just like you can use them to find the area under a curve, to find a curve length, however that proved too time consuming and way too much error. To find the arc length you have to integrate, using the derivative of the equation.

Integrate, on the bounds of a and b, where a = o and b = 80, the sqaure root of (1 + (the derivative of y) squared). In other words...

y = 160-(x^2/40) so... dy/dx = 0 - x/2 or x/20.

Now integrate from a to b (1 + (dy/dx)^2)^.5 where the exponent of .5 is the square root of the whole thing, since these forums dont support any mathmatical symbols or eve sub/super scripts

integrate from 0 to 80 (1 + (x/20)^2)^.5 and you get 185.8713505 meters.

heres a picture....i had to make it a negative because the pencil was so light...

[TOloseGT]

mad props to vindicator. i saw that prob and immediately thought free fall. didn't even think about calculus. i was wrong =[

[Vindicator]

mad props to vindicator. i saw that prob and immediately thought free fall. didn't even think about calculus. i was wrong =[

I did the same exact thing at first too...only my "solution" was less logical than yours at first

[Maniac]

e^(2x)-e^x + 5 = 11
e^(2x) - e^x = 6
2x - x = ln6
x = ln6

too easy....how about you add something like...*wait a moment while i go make it into a pic so its easier to read*

Heres some fairly easy questions:

1. Find the derivative of LOG5(x^2 + 3x - 1)

*hard to do on here, that is: log base 5, of x squared minus 3 x minus one.*

2. Integrate 6^(5x)dx with respect to x.

3. Find the integral of tanx dx with respect to x.

4. A mass tied to the end of a spring moves along the path S(t) = A sin(wt + ) where A = amplitude, w = omega, t = time, and = phi (displacement from start). If the mass is pulled down and let go, what equation best describes its velocity when S(t) is at a minimum when t=0

Id still like to see someone solve my begginer integrals and derivative questions, and if anyone can figure out the physics spring question.

Here I solved all your problems. Answers are highlighted... some are identities of each other.

[Vindicator]

e^(2x)-e^x + 5 = 11
e^(2x) - e^x = 6
2x - x = ln6
x = ln6

too easy....how about you add something like...*wait a moment while i go make it into a pic so its easier to read*

Heres some fairly easy questions:

1. Find the derivative of LOG5(x^2 + 3x - 1)

*hard to do on here, that is: log base 5, of x squared minus 3 x minus one.*

2. Integrate 6^(5x)dx with respect to x.

3. Find the integral of tanx dx with respect to x.

4. A mass tied to the end of a spring moves along the path S(t) = A sin(wt + ) where A = amplitude, w = omega, t = time, and = phi (displacement from start). If the mass is pulled down and let go, what equation best describes its velocity when S(t) is at a minimum when t=0

Id still like to see someone solve my begginer integrals and derivative questions, and if anyone can figure out the physics spring question.

Here I solved all your problems. Answers are highlighted... some are identities of each other.

img

you only needed to answer number 4 the rest have been answered. Although, with the information given, you can replace phi.
edit: perhaps i underestimated this forum and people here actually know what they are doing...time for harder stuff.

[Maniac]

WOW! I just wana slap the shit out of myself for being so stupid. I got it. The problem is that the equation does not provide a circle for which to use theta = arc / radius or any other geometric / trigonometric equation. So the answer is in calculus.

Good job bro... I was reading the first four pages and I was wondering why it can cause so much confusion. By the time I work out all the problem (10 minutes), you already figured it out.

And regarding your first sentence, I think we've all been there before. Nothing to be ashamed of lol.

[Maniac]

e^(2x)-e^x + 5 = 11
e^(2x) - e^x = 6
2x - x = ln6
x = ln6

too easy....how about you add something like...*wait a moment while i go make it into a pic so its easier to read*

Heres some fairly easy questions:

1. Find the derivative of LOG5(x^2 + 3x - 1)

*hard to do on here, that is: log base 5, of x squared minus 3 x minus one.*

2. Integrate 6^(5x)dx with respect to x.

3. Find the integral of tanx dx with respect to x.

4. A mass tied to the end of a spring moves along the path S(t) = A sin(wt + ) where A = amplitude, w = omega, t = time, and = phi (displacement from start). If the mass is pulled down and let go, what equation best describes its velocity when S(t) is at a minimum when t=0

Id still like to see someone solve my begginer integrals and derivative questions, and if anyone can figure out the physics spring question.

Here I solved all your problems. Answers are highlighted... some are identities of each other.

img

you only needed to answer number 4 the rest have been answered. Although, with the information given, you can replace phi, and it should be negative,not positive.
edit: perhaps i underestimated this forum and people here actually know what they are doing...time for harder stuff.

There shouldn't be anything negative in your physics solution. You must have done something wrong.

you only needed to answer number 4 the rest have been answered.

I didn't see anyone solving #3 or #4. #2 was solved using the long, slow, and ugly way Since there were 3 problems to be solved, I might as well do #1 to make it complete

[Vindicator]

lol...once again i caught myself. When deriving acceleration it isnegative Im just gona stop doing math for today

[Maniac]

lol...once again i caught myself. When deriving acceleration it isnegative Im just gona stop doing math for today

Oh come on now don't give up so easily... math is fun

[ThiefzV2]

Anyone knows how to solve the NaOH molarity problem?

[crazyskwrls]

i am not sure if i understood the molarity question correctly i think some thing is missing 50% means 50% by mass, mols, or what?

[StealMySoda]

For the mass question.

If its 50% mass NaOH, if its solution its in water. So:
H - 1
O - 16
Na - 23

23+16+1 = 40
h2O = 18

Lets say....we have

40g of NaOH in 1 liter would give us a 1 molar solution.

1 liter of water 1kg.

So technically if we have 1000g of NaOH in 1000g of water, it would be 1000/40=25molar.

Wow. That doesn't sound right at all.

Time to try another method.

[ThiefzV2]

Wow. That doesn't sound right at all.

Time to try another method.

lol yeah. I was about to say.

Answer is 19M even though I have no idea to arrive at that and ive tried everything u tried other methods yet

Hershey, u good at chemistry right?

[/Pi]

Yeah, it was 19M. But can you figure out what you did wrong in the chemical eq?

I'm going nuts. I can't find my error. If you get the solution, can you post it here? My GenChem has been rusty for quite some time.

[Maniac]

lol...once again i caught myself. When deriving acceleration it isnegative Im just gona stop doing math for today

So Vindicator... did I get the other 3 problems right also?


And regarding that molarity problem, I will tackle it tomorrow if I remember. Doesn't sound that complicated. Probably it's best to set up the problem using dimension analysis.