Silkroad Online Forums

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

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.

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

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

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.



Been said , props for the nice graph though.

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

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

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.

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

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

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?

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.

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

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.

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.

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

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

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...

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

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

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.

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.

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




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

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

Anyone knows how to solve the NaOH molarity problem?

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?

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.

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?

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.

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.