Homework Help: Can someone explain to me what i did wrong on this quiz? waves

1. Apr 5, 2006

mr_coffee

hello everyone. I'm studying for the exam now and I understand if a wave is moving in the negative x direction to the left, the value infront of the x should be positve. But you see where he took off -1/2, because i wrote down m/s? Do you know why? its v^2, i thought that just means take the value of v, square it. should it have been m^2/s^2?

http://img112.imageshack.us/img112/5643/lastscan4bc.jpg [Broken]

Thanks!

Last edited by a moderator: May 2, 2017
2. Apr 5, 2006

looks like you go to PENN STATE
Physics 211 212 213 214

SORRY I CANT HELP, but i thought your class looked like a penn state class 214, just got me happy! sorry lol

Last edited: Apr 5, 2006
3. Apr 6, 2006

topsquark

Yes, it should have been m^2/s^2. Note that the d^2y/dt^2 is in m/s^2 and the d^2y/dx^2 is in 1/m.

So:
$$\frac{m}{s^2}=(unit)\frac{1}{m}$$

$$\frac{m^2}{s^2}=(unit)$$

-Dan

4. Apr 6, 2006

mr_coffee

Ooo thanks topsquark!
and yes I go to Penn state hah! I'm assuming u also went there or go?
I'm a Computer Engineering Major, wee!