IEEE Consultants' Network of Long Island

Coriolis Effect or Coriolis Force? - Dick LaRosa

 For a projectile going through thin air over some spot on the Earth, there is essentially no Coriolis force. The projectile passes over a particular spot on the Earth at t=0. A coordinate system, whose origin is at that particular spot, is locked to the Earth surface with its x-y plane tangent to the surface. This coordinate system rotates about its z-axis through an angle

t omega sin(latitude)

in a small time interval  t. Omega is the angular rotation rate of the Earth about its polar axis. The projectile is moving at velocity  v, so its lateral displacement from the point where it would have been in a non-rotating coordinate system is

Perception of Transparency - John Dunn, Consultant, Ambertec, P.E., P.C.

Does the sketch below represent a partially transparent yellow circle lying on top of a red rectangle or does it represent a partially transparent red rectangle lying on top of a yellow circle?

Current Flow - John Dunn, Consultant, Ambertec, P.E., P.C.

There may still be sounds reverberating at this place where I once heard a really HOT argument going on over the question "Which way does current flow, from positive to negative or negative to positive?". The opposing sides came from different industries in which the conventions of current flow seemed to be opposites of each other and each side was absolutely certain of being in possession of absolute, divine and irrefutable truth.

It may be an apocryphal story, I really don't know, but I once read that we should blame Benjamin Franklin for this problem. The story was that when he charged up his Leyden jar during his lightning experiment, he arbitrarily chose to call one post of the jar "positive" and the other one "negative" and he thereby set the precedent which was that as the Leyden jar was discharged, current flowed out of the positive post and into the negative post. Had he known what electrons were, he might have set the precedent the other way.

Insects and Yellow Light - John Dunn, Consultant, Ambertec, P.E., P.C.

Some years ago, I was listening to "Crockett's Victory Garden" and the man spoke of reducing a white fly infestation on a caller's plant. He said to take a yellow Prestone anti-freeze container, cover it all over with a thin layer of petroleum jelly and set that container down next to the infested plant. The theory was that the white flies would be attracted to the yellow plastic and get stuck in the petroleum jelly coating.

Then, the next thing I notice is that so-called "bug lights" for use outdoors emit yellow light which is not supposed to attract insects to one's front door.

Can somebody tell me what's going on here? Are some insects able to see yellow and others not? Is there a significant spectral difference between the transmitted yellow light of the bulb versus the apparent yellow of the Prestone container's retransmission of incident white light or daylight?

Learning Stuff - Dick LaRosa

I have to figure out whether sea water can be lifted and distributed over the solar-heated evaporator panels using capillary action. The Hausmann and Slack text that I used in 1942 was on loan to our grandson, so I went to a local public library  and searched "capillary action" and "surface tension". Nothing came up so I searched "physics". When only a juvenile book and an encyclopedia showed up I went to the stacks and found some books on college physics. There seems to be a semantic problem that excludes college physics from just-plain-old physics, but I did not pursue that distraction because a book by Serway and Faughn had what I needed. Other books on the shelf and the physics encyclopedia made no mention of the subject. A Van Nostrand Scientific Encyclopedia had some material that seemed incomprehensible and incorrect to me.

 

NASA and SpaceX by Jerry Brown

Success of the SpaceX Falcon 9 launch is terrific news.Getting NASA out of the business of manned space flight is way overdue.

I'm a 71 year-old scientist/engineer who grew up dreaming of traveling to the moon. I can still recall the excitement I felt watching the 1950 movie "Destination Moon". So, no one was more thrilled when Neil Armstrong set foot on it. But even in the early stages of the space program, it was clear that the shuttle was a brute-force solution with no long-term future. This first became evident to me when I learned about the glued-on heat tiles that would have to be repaired in a labor-intensive process after each flight.

Driving distracted - by Jerry Brown

Driving is, by far, the most dangerous thing we do on a daily basis. At 30 mph, two cars approaching each other travel a combined distance of 88 ft in one second and when you consider that in most traffic situations we’re much less than 88 ft from other cars, that means you are constantly less than 1 second away from a potential collision EVEN IN TOWN AT 30 MPH. To me, that means that unless you’re driving on the Nevada salt flats, you can’t afford ANY distractions, especially if you’re in the car alone.

Furthermore, talking on a cell phone hands on or off is distracting and most of us don't really appreciate what distraction does to our situational awareness.This site does a good job of demonstrating the problem. Driving distracted