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

AI Thread Summary
The discussion revolves around a quiz question related to wave physics, specifically the correct units for velocity and acceleration. The original poster is confused about receiving a deduction for writing "m/s" instead of the correct "m^2/s^2" for velocity squared. Participants clarify that the units for acceleration involve "m/s^2" and that "d^2y/dx^2" has units of "1/m." The conversation also includes a light-hearted exchange about attending Penn State. Understanding the correct application of units in physics is crucial for accurate quiz responses.
mr_coffee
Messages
1,613
Reaction score
1
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

Thanks!
 
Last edited by a moderator:
Physics news on Phys.org
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:
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
 
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!
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top