Quick Physics question...

[Zeeky Boogy Doog]

I'm almost positive that I have the correct answer, but it is telling me that I am wrong. The assignment is online, and I believe that the answer that is in for the y-displacement is incorrect and that I am right, however I might be wrong, and as such I'm asking for help... I can submit the answers I have as I get them, which is how I know that the answers I have so far are correct.

A fish swimming in a horizontal plane has velocity vi = (4.00 i - 4.00 j) m/s at a point in the ocean whose displacement from a certain rock is ri = (10.0 i - 4.00 j) m. After the fish swims with constant acceleration for 24.0 s, its velocity is v = (25.0 i - 5.00 j) m/s.

the acceleration comes out to be:
ax = (25-4)/24= .875 (confirmed correct)
ay = (-5-(-4))/24=-1/24= -.042 (confirmed correct)

Where is the fish at t = 32s?

displacement = inital displacement + inital velocity x time + .5 x acceleration x time^2
x displacement = 0 + 4(32) + .5(.875)(32)^2 = 576 (confirmed correct)
y displacement = 0 + (-4)(32) + .5(-.042)(32)^2 = -149.504 (says I am wrong)

I've been at this one for quite some time now, and everything I've tried has come out wrong, all of the other answers I'm sure are wrong, but using the exact same formula, I should come up with the right answer, but apparently I am not.
Anyone able to lend me a hand?
Thanks in advance.

Edit: added link for extra confusedness

 

[Inspector Jihad]

utexas?

 

[Zeeky Boogy Doog]

Originally posted by: Inspector Jihad
utexas?

what? I'm not Texas, nor do I go there...

 

[silverpig]

Okay your math looks right, but I think there's some ambiguity in the question. Maybe try putting in the answer as -145.504. Are we talking displacement from original position, or displacement from the rock? Considering your first answer was right for the displacement, it's probably from the original position, which should make your second answer right as well.

Of course every time I made a mistake in those physics classes it was due to some stupid math error that a kid in grade 8 could have picked out.

 

[Zeeky Boogy Doog]

Originally posted by: silverpig
Okay your math looks right, but I think there's some ambiguity in the question. Maybe try putting in the answer as -145.504. Are we talking displacement from original position, or displacement from the rock? Considering your first answer was right for the displacement, it's probably from the original position, which should make your second answer right as well.

Of course every time I made a mistake in those physics classes it was due to some stupid math error that a kid in grade 8 could have picked out.

Yeah, I tried that as well already, one of the many answers that showed up as wrong as well, I checked and rechecked my math, had someone else check my math (though I had to explain what everything was before he could be of any help ) and just wanted to check one more place before I declared the computer wrong instead of me, and so thats good enough for me that I'm right.

Thanks!

 

[Ready]

Yes the answer is 5

 

[twitchee2]

waht do the "i" and "j" stand for?

 

[LongCoolMother]

Originally posted by: twitchee2
waht do the "i" and "j" stand for?

vertical and horizontal components

 

[Tylanner]

barracuda

 

[twitchee2]

ok that waht i thought im

 

[Fenixgoon]

for X/Y respectively, you use position = initial + intial velocity (t) + 1/2 (acceleration) t^2 for the first 24 seconds

then the last 8 seconds you use the full velocity and calculate the displacement for that (and then add the two together of course)

....right?