Joatmon

Later - just had another look and I now have the diagram - anyone know why I lost it earlier?

How lovely to hear a proper contralto singing voice. Now for something different. Perhaps we are all prisoners of some sort?

Because the machine has a technical system (say moving heat detector ) that can detect a life form at a distance, but being short sighted it needs to get up close to properly identify the specimen. Hear is a more serious attempt which I will hide:-

If you google "frequency modulation" and then "amplitude modulation" you will easily find this information.

Help! Last time I looked at this post I am sure that I saw the diagram. Now I only see what I attach . Would anyone like to tell me the kind of picture it is and what it should be opened with? I am not aware of making any changes to my computer.

Because the ball was short sighted and it wasn't until it got close enough that it realised it already had 3 specimens of homo sapiens.

From the link:- http://en.wikipedia.org/wiki/Human_evolutionary_genetics#Sequence_divergence_between_humans_and_apes "Genetic distance. Given below the diagram, the genetic difference between humans and chimps is less than 2%,[3] or 20 times larger than the variation among modern humans." This seems to support the OP?

The idea gets more attractive the older you get.

Lovelorn Lala sombre downcast in morbid adulation of the worthless lift thine eyes blue vastness yours to command brightness your possibility dismiss turmoil Accept peace and live

You console her your way and Mike can.............. Couldn't be a tiny bit jealous could you?

Looks like I got my wires crossed! Now considering the angle HPG, do we agree that its maximum angular velocity occurs at Top and bottom dead centre? I think everyone does. Now an unresolved question seems to be at what angle does the angular velocity become null? The angular velocity will be above zero and less than maximum when the angle is as shown (at 60 degrees). My first thought, which I now have doubts about, is when the angle GHP is 90 degrees.

I based my opinion on the fact that the line PH (extended) makes a tangent with the circle. My first thought was any further rotation would reduce the angle HPG, but on second thoughts this doesn't take into account piston movement. I think your answer may well be correct! I'm no mathematician, just trying to visualise what happens with a technician's eye! lol.

I think that the maximum piston speed is when angle GHP is 90 degrees? (P being the piston bearing centre)

The main difficulty, as I see it, is your friendship in this arrangement. If it was a situation concerning strangers you would treat this as a job, do your best, accept a fair amount of pay for your efforts and not be too concerned about the end result. I guess I am saying that whether Holly should, or should not proceed with the course is not really a decision for you to make. I don't think you should personally agonise about whether she is wasting her time (and yours). Although it may be difficult for you to avoid, giving her so much help that what she achieves is as much about your input than hers is (IMO) wrong. My advice would be to treat her as you would anyone else. If she can't make the grade she will soon come to realise this for herself. Alternatively the course assessment procedures will solve the problem for you. When this happens be a good friend and offer "a shoulder to cry on".

I think the shading under the triangle under the bearing at G is supposed to indicate it is fixed.I think we can assume the cylinder is fixed. In other words I think we can assume the normal relationship between piston and crank assembly (e.g. as in a car engine). This means in the two positions where HGP is a straight line the angular velocity will be at its maximum and when angle GHP is 90 degrees the angular velocity will be zero. (NB point P is the small end bearing) Therefore when the angle is 60 degrees the angular velocity will be somewhere between its maximum value and zero.

Since the angular velocity will change with angle I also presume the same. I am not very good with maths - come in Imatfaal!

Your idea of the electrons going to and fro is correct. Ignoring the relatively few electrons at the ends of the conductor which enter and leave the alternator driving the ac current you can say the electrons do not come out. The same electrons just go to and fro. On average the speed of the electrons is zero. The actual speed of the drift of electrons as they go to and fro changes from zero to a maximum and back to zero, first in one direction and then in the other direction. This keeps repeating. You can find quite a lot of information using Google - for example:- http://www.allaboutcircuits.com/vol_2/chpt_1/1.html

"Does anyone know whether it is possible for someone to get Herpes from a toilet seat?" It's possible, but it's best to wait until he's finished.

I know, but I threw this in because #4 might give the impression the effective speed of an electric current is instantaneous and #4 might give the impression that the effective speed is that of light.

The piston is a complete lump of material that slides to and fro in the cylinder under continually changing speed. As I understand the question I think you are asked to calculate the speed when the crank is at 60 degrees. The fact that P is not shown on the centre line does not affect the answer - its just a marker on the cylinder wall. I notice P is under the piston small end bearing (although not essential to the question, but probably meant to be helpful). I think the triangle G, H, Small end bearing is valid in the calculation.

Because the piston speed varies with the angle.

A change in voltage, e.g. a pulse, will travel along a conductor at less than the speed of light. This speed is sometimes pre-decided by using capacitors and inductors to make a "delay line". Typical velocity factors "Velocity factor is an important characteristic of communication media such as Category 5 cables and radio transmission lines. Plenum data cable typically has a VF between 0.42 and 0.72 (42% to 72% of the speed of light) and riser cable around 0.70. A VF of 0.70 corresponds to a speed of approximately 210,000,000 m/s or 4.76 ns to travel one meter. Some typical velocity factors for radio communications cables are provided in the ARRL Handbook[4]:" http://en.wikipedia...._of_propagation

I like,although you're young and bright, You cannot say you're always right. Now and then you give me, lass, A little chance to kick some ass!

If you say Your going away hear what I say Please stay Don't spoil my day