Recent content by nateja

Homework Statement A sample of Mo-101, initially pure at time zero, beta decays to Tc-101 which then beta decays to Ru-101 (stable). The half-lives of Mo-101 and Tc-101 are nearly the same and for this problem are assumed equal (14.4 min). After a decay period of one half-life how many atoms...

That makes sense for number 3... kind of like 'skew' planes is how I"m thinking of it.

Ok, I'm right with the last 3! I reread the planes section and it states "two planes are parallel if their normal vectors are parallel"... which is confusing now because I realize that if I factor out a negative for two opposite directional vectors then I'll get the same vector... same as a...

Ok... Thanks for the number 5 clarification. I now understand that parallel means not touching and same direction. So my guess for number 4 is that it is True. A line will intersect with a plan always - unless it is parallel. Number two was a misunderstanding on my part. I was thinking of...

Are two lines parallel if they lie on parallel planes?? I'm starting to see the difference here between parallel and skew. I hope I'm not asking too many questions... it just helps to think it out sometimes.

I have a few more True or False questions: Two planes perpendicular to a third plane are parallel? I said T because I thought the same plane would be considered parallel - like with vectors. But I feel like this is considered an intersection. Two lines perpendicular to a plane are...

Homework Statement The question states True or False: Two lines parallel to a third line are parallel Homework Equations You need to know the difference between skew, parallel and perpendicular The Attempt at a Solution I thought of three parallel planes (which have an infinite...

Also, Laplace inverse of s/((s+1)^2+1) + 2 * 1/((s+1)^2+1) does not work out either. The first term is close to the laplace of e^(at)*cos(bt); however, it is not exact again. The second term will be 2*e^(-t)*sin(t) I can't see any way to tinker with the algerbra without adding on new...

I got this. I also noticed my mistake in completing the square and solved that. I got (s+1)^2 +1 for the denominator now. So I should get the inverse laplace as uπ(t)*t*e^(-t) + ? I am getting (s+2)/((s+1)^2 + 1) which does not have an inverse laplace in the chart. The nearest thing is...

I tried to use complete the square on the denominator to see if I could break it up more. I got s = -1 + i and s = -1 - i... so I don't know what to do with that at all. I'll keep trying though...

and just to explain, π is pi and δ is delta for dirac delta function

Homework Statement Find the solution of the givien initial value problem and draw its graph y''+2y'+2y = δ(t-π) y(0) = 1, y'(0) = 0 Homework Equations A Laplace transform chart would be very useful The Attempt at a Solution I chose to solve the equation with Laplace...

Thank you, mfb and vela!

So we get f_f = f * sqrt((1+v/c)/(1-v/c))*sqrt((1+v/c)/(1-(v/c)) plug in the values f = 33MHz and v = .5c f_f = 99MHz We switch the equation to f_f = f*sqrt((1+v/c)/(1-v/c)) because the light and mirror are approaching each other. Correct? or semi-correct?

I get what you mean that if the answer is 11MHz the mirror must be moving away. This makes sense because the light will be compressed (thus increasing frequency) for a mirror moving toward us. So, from both of your explanations, I'm understanding the following. Please correct me if my...