Recent content by stfz

Hmm. I was under the impression that the static friction present was a friction force and hence the there are non-conservative forces at work. However, now that you mention it, I realize that static friction, by definition, can do no work. Hence there are no non-conservative forces doing work...

This isn't about a specific physics problem, but rather a question: Given I have a ball or cylinder rolling smoothly along some path, is it generally true that mechanical energy is conserved? I.e. if ##E_mech = K+U = K_{trans} + K_{rot} + U##, then ##\Delta E_mech = 0##? I have been able to...

Well total momentum in primed frame would be ##p'=\sum m_i v_i'##. However, initially the balloon is stationary with respect to the ground, and so is the man. Hence the man is stationary with respect to the balloon? Yes, the velocity of the balloon (initially)in the primed frame is initially...

According to my (flawed) reasoning, initially, before the man moves, there is zero momentum in the primed frame. Also, I know that momentum cannot change, so during/after motion, momentum in primed frame is zero. I know I'm wrong somehow, but I still can't see it :(

Homework Statement A 52kg man is on a ladder hanging from a balloon that has a total mass of 450kg (including the basket passenger). The balloon is initially stationary relative to the ground. If the man on the ladder begins to climb at 1.2m/s relative to the ladder, (a) in what direction does...

Yes this makes sense. Thank you!

Sorry about that. Here's the full question: A small ball of mass m is aligned above a larger ball of mass M (with slight separation) and the two are dropped simultaneously from a height h. Assume the radius of each ball is negligible relative to h. (a) If the larger ball rebounds elastically...

Homework Statement The classic double ball drop question: a ball of mass m is placed directly above another ball of mass M, and assume that m is not negligible. Both balls are dropped simultaneously. Find the mass m such that, upon the second collision (m with M), M has a final velocity of...

I've come across a question which is asking what would happen in a cell with odd diploid number 2n=15 when it undergoes meiosis. Here's my thinking: - 15 chromosomes, so 7*2 homologues + 1 loner? - Hence, after Meiosis I, we'd have 7 chromosomes in one cell, and 8 in the other? - After meiosis...

Hi all, I've been self-studying a first year uni introductory mechanics course, and I'm confused with the derivations involved in calculating the final state of an elastic collision in one dimension, given the initial state. So basically we have masses of m_1, m_2 with initial velocities v_1i...

Homework Statement I'm trying to see the relationship between the negative sign (Lenz's Law) in Faraday's law. It states that EMF is equal to negative flux change. I understand how to use Lenz's Law to find direction of current and hence EMF, but I am not seeing the relation between the neg...

Homework Statement My Physics course does not give an in-depth overview of electrostatics at all (it is rather shallow, focusing on electronics and circuit analysis). However, I find that I really need to understand it fully to form the basis for magnetism and generation. So... I have a few...

Homework Statement Use the substitution ##x=X+h## and ##y=Y+k## to transform the equation ##\frac{dy}{dx}=\frac{2x+y-3}{x-2y+1}## to the homogenous equation ##\frac{dY}{dX}=\frac{2X+Y}{X-2Y}## Find h and k and then solve the given equation Homework EquationsThe Attempt at a Solution If I...

Hi, I've been working on a school project which involves investigating the momentum before and after a collision between two steel balls. E.g. we have Ball A (moving) and Ball B (stationary), which are of identical mass. Ball A collides into Ball B. What we have observed is that Ball B then...

Thanks for answering my question. I found this website which is quite helpful http://www.7stones.com/Homepage/Publisher/Circuit.html