Recent content by James_Frogan

Thanks atyy, Ygggdrasil and bobze. I omitted the mutation that occurs to adapt to environments and the various other factors mentioned. About the Hardy-Weinberg problem, doesn't the recessive trait population q^2 require a large enough sample size? For the first person that received a...

Hi everyone, I'm studying physics and not biological sciences, but I've been wondering about recessive genes recently. Given my background, do be kind on the explanations. My question is: if a recessive gene tends to be overcome by the dominant gene, how do recessive traits still display...

Thanks Spinnor, I am aware of rolling resistance, but I believe that angular velocity of the wheel is a function of only the power required to overcome rolling resistance; whereas I am looking for a force (not power) that has velocity as a dependent. More specifically I am looking for a...

Good afternoon, I've tried to find a simplified model for the dynamic forces acting on a rolling wheel, but have had very limited success. I'm looking for a force that is proportional (or related to) the rotational velocity of the wheel (rotational damping) because of the contact point of the...

Thanks Mbert, I came across several articles on how to convert the angles themselves to quaternion, however the equations of motion are in the forms of: \ddot{\phi},\ddot{\psi},\ddot{\vartheta} = f(\phi,\psi,\vartheta,\dot{\phi},\dot{\psi},\dot{\\theta}), so I cannot apply the conversions in...

Thanks Mbert, unfortunately the case I am looking at causes the top to rise to the steady position.. which unfortunately is the theta 0 position. Looks like I'll have to dwelve into quaternions. Is it possible to 'convert' my equations in Euler angles into quaternions if I have the equations...

Hi all, I've formulated using Lagrangian formalism the equations of motion for a spinning top. I know about the gimbal lock/singularity that occurs at theta=0 and I was wondering if there was any other way to do it without dwelving into quaternions. Yogi published a paper "A Motion of Top...

Thanks for the explanation. I merely assumed that "the angular velocity about the body z axis" was just the top's spin rate. Why does it stay as a constant of motion, but not \\omega_1 and \\omega_2?

I refer to the derived motions of equations here: http://www.maths.surrey.ac.uk/explore/michaelspages/Spin.htm Don't the derivations show that the rotation'' (ie psi'') is not equal to zero? Or am I confused with something else?

D H, if you take into account the nutation, the spin rate will not be constant but will have a slight sinusoidal increase/decrease in speed as the kinetic energy is passed between nutation and precessing. If however the case were constant precession (no nutation) then the spin rate would be...

I'm particularly interested in the motion of tops, from what I understand, I would have to go with Cleonis on the perpetual motion of the top. Assuming that there is no external torque or work done (i.e. the Lagrangian equations of motion simply consists of the derivatives of the kinetic and...

ψε∫ thank you! hahaha :P no really, you've been a great help :D thanks!

tiny-tim, oh dear. Physics is so mean to me :ρ now τorque comes in. Haha. Isn't torque irrelevant if it's spinning on a tip? (or perhaps just close to zero)

Hi cupid.callin, My guess (from what I've been reading) is that because in the theoretical we assume that the contact is perfectly flat. However in reality, for an object with a larger surface area, there will be more microscopic pimples/dimples/ridges that lock together with the contact...

Oh wow that's interesting. So effectively I can slide an object with 3 sharp points of contact and another with equal mass but 15 points of contact and it wouldn't make a difference if they are all rigid? And it doesn't matter if it's spinning or translating? For friction in Lagrangian...