Recent content by davidphysics

Yea we told our teacher, so now the t= 4 seconds, and obviously now the problem is super easy. W=Pt W= 40 W (4 s) W=160 J

[SOLVED] Light Intensity question The light (electromagnetic) output of a bulb is 40 W. How much energy passes through a 40 cm^2 area element aligned perp. to the light rays? I know that I = Power/Area, but I thought that Power = W(aka. energy) /t , and the problem has no reference to time...

Nevermind - I figured it out. I was making it much too difficult. All I had to do was Po=Pf for the horiz and vert, and solve that set of equations.

Hi. I am still having trouble and would like help. Its not working out. Thanks

I mean the initial VERT momentum. But thanks for "The initial kinetic energy is not zero either, since A is moving." Can't believe I screwed that up. I don't have any more time now, but I'll work on that tomorrow and will come back to this forum later. Thanks! and cya

Wow, then that image is very deceiving... thanks for your help -Everyone else JUMP IN! :) Just thinking of it that makes perfect sense, now I see how these pictures mess with your mind. Disregard everything above, yea so the Vert momentum up = vert momentum down

Bump (sorry)

O didn't realize that, please read my post that I just posted a second ago, and I'll put the image on imageshack. POSTED:http://img135.imageshack.us/img135/9303/0732jj6.gif And when I plug in the values for "v" in those formulas I should use for example Vacos65 and Vasin65 for the horiz and...

And when I plug in the values for "v" in those formulas I should use for example Vacos65 and Vasin65 for the horiz and vert respectively, right? For some reason I keep getting the Vert for a and b=0, because both the initial momentum and kin energy=0. So when I solve I get Vert: Va=Vb=0... I...

Ok sorry let me explain what I've gotten to... Basically I've set up both horizontal and vertical equations for both Po=Pf and Ko=Kf. Before I go any further, am I correct to assume that it is elastic and that the kinetic energy is conserved? To be honest I don't wan't to use up my 4 trys on...

Hey. This is my first post... here's my question [Diagram Attached]: The drawing shows a collision between two pucks on an air-hockey table. Puck A has a mass of 0.028 kg and is moving along the x-axis with a velocity of +5.5 m/s. It makes a collision with puck B, which has a mass of 0.068 kg...