Examples of Forces in Everyday Life and How They Affect Things

© Eugene Brennan

In this first part of a two-part tutorial, we'll learn the absolute basics about forces!

What's covered:

• Definitions of force, mass, velocity, acceleration, weight
• Vector diagrams
• Adding and resolving vectors

What Is a Force?

We can think of a force of a force as a push or pull.

 

Newton's 3 Laws of Motion: Force, Mass and Acceleration

An infographic explaining Newton's three laws of motion. © Eugene Brennan

Mechanics is a branch of physics which deals with forces, mass, and motion.
In this second part of a two part tutorial, you'll learn the absolute basics!
In the first tutorial, Examples of Forces in Everyday Life and How They Affect Things, we learned what force is and explored the various types of forces in the world around us.

What's Covered in This Guide?

• Newton's three laws of motion and how an object behaves when a force is applied
• Action and reaction
• Friction
• Kinematics equations of motion

From the article "Examples of Forces in Everyday Life and How They Affect Things". © Eugene Brennan

Replica Gun Discussion on Liveline

Created by Grok.

A discussion on RTÉ Liveline today was about "Airsoft" type guns on public display in shops. Under the Firearms Acts 1925, revised to 2023, these guns must have a muzzle energy of less than 1 joule to avoid being classified as firearms requiring a license.

What's a joule?

It's the Système International (SI) unit of energy or work done.

Energy = power x time

So 1 watt for 1 second = 1 x 1 = 1 joule.

Think of a 1 watt bulb turned on for 1 second; that consumes 1 joule of energy.

Big Picture Science Podcast: A Real Gas

Created by Grok

Did you know, some gasses have a colour (like chlorine), many are invisible and have have no taste or smell (such as oxygen and nitrogen), and yet others are totally unreactive—the noble gasses, such as neon, argon and xenon? Also steam is an invisible gas. The stuff we see coming out of a kettle is condensed steam, but close to 100 degrees Celsius.

In this episode, Mark Miodownik – Professor of materials and society at the University College London and the author of It’s a Gas: The Sublime and Elusive Elements That Expand Our World, talks with executive producer of BPS, Molly Bentley.

Items for Sale in Kilcullen, Circa 1900

Image courtesy The National Library of Ireland.

"Sides of pork, brooms, Cadbury chocolate and cocoa and The Freeman's Journal: some of the items for sale in Kilcullen circa 1900."
 
I've been examining photos from the Lawrence Collection again and zooming in to see whether I can spot any details I may have missed. The collection is available online on the National Library of Ireland's website. I first viewed the photographs on a visit to the NLI around 1982. In those days, before digitisation, photographic records were stored on rolls of microfilm and had to be viewed using optical microform readers.
The Lawrence Collection consists of approximately 40,000 glass plate negatives of buildings and scenes from life in Ireland, photographed between 1865 and 1914. The photographs were taken using large-format cameras and because of the size of the glass-plate negatives, resolution is quite high. There are 25 photographs of buildings and streetscapes in Kilcullen and its hinterland, and the collection became available to access online over 10 years ago.

You can view it here.

All images courtesy the National Library of Ireland.

The building at the corner of the entrance to the Valley Park, originally Andrew Maloney's premises.

 

Signs for "The Freeman's Journal" outside what is now Bardon's Pub. The premises was originally a hotel and then a pub and grocery.

A shop in Upper Main street which is now the premises of Dowling Property.

Near Centric Health.

Dublin House, now Woodbine Books. It was the premises of Denis Brennan, auctioneer, pub and drapers.

Leaky Schrader Valve

Hand truck tube. © Eugene Brennan

So being a member of 60 Facebook groups and squandering a lot of time nattering about all sorts of things, I try to get at least one useful thing done per day. Today was damp, so dealing with weeds in the driveway was out of the question. One of the items on my ever-growing-longer "to do" list I hadn't got around to was fixing the wheel on my hand truck which always seemed to be soft when I went to use the truck. I thought it might be a puncture caused by running over thorns (what usually happens with the bike). However doing a water test showed the Schrader valve was leaky. There's a special tool for taking the innards out of the valve casing, but I usually just use a needle-nose pliers. These valves have a conical part that sits into a conical seat, the cone being pressed against the seat by a spring. I blew out the valve with compressed air, gave the red ring that seals against the valve body a wipe and put the bits back together. This time there were no leaks whatsoever after the water test.

Removing the Valve innards. © Eugene Brennan

C

Check valve. © Eugene Brennan

© Eugene Brennan

Airbus A320 Incident, Air Travel and Cosmic Radiation

Image created by Grok

Airlines worldwide have grounded their Airbus A320 fleets to carry out urgent software updates following an incident in October, when a JetBlue aircraft on a flight between the US and Mexico suddenly lost altitude after a pitch-down event, without any pilot input. According to a BBC report, "Around 6,000 A320 planes were thought to be affected," but many were able to fly again within hours after undergoing the software update. It's thought that the glitch on the JetBlue aircraft was caused by corruption of data in flight avionics computers, responsible for calculating elevation. A press release by Airbus on 28th November mentions "intense solar radiation" as being the possible cause of the recent event.

Cosmic radiation, consisting of high energy particles, mostly originates from the Sun, but also from the remnants of supernovae in our galaxy, the Milky Way, and other distant galaxies. It's more intense at higher altitudes where the thinner atmosphere has less of a shielding effect. The Earth's magnetic field also protects us from cosmic radiation, by steering particles safely into the poles, generating the spectacular phenomenon of the Northern and Southern Lights in the process. Cosmic rays can affect electronics, and there have been cases of glitches in satellites. According to a Scientific American article, "Extensive background radiation studies by IBM in the 1990s suggest that computers typically experience about one cosmic-ray-induced error per 256 megabytes of RAM per month."

This article from the EPA provides some further information on cosmic radiation and outlines its effects on passengers and crew on aircraft. 

Kilcullen Market House?

Excerpt from the c. 1837 6" first edition OSI map. Courtesy Tailte Éireann.

A building in the square, visible on the c. 1837 6" first edition map. By the time the 25" map was surveyed circa 1890, the structure had disappeared.

We'll probably never know what it was. I haven't found any records mentioning it. Possibly it was just a house that remained from a terrace of buildings that once stood along an earlier street line.

 

The building had disappeared by c. 1900.  Image courtesy Tailte Éireann.

 

Maps courtesy Tailte Éireann from their Irish Townland and Historical Map Viewer

Carlow Stables Remains

© Eugene Brennan and map courtesy Tailte Éireann

A fragment of brick from under my front lawn. I can't think of any other way it got there, other than rubble from the demolished stables being bulldozed to act as infill during construction of the Nicholastown housing estate, which opened to residents in 1939. I found it at a depth of over 3 feet when digging a soakaway in 2020. Bricks were sometimes used in flat arches above windows and for the window jambs of rough-stone buildings.

The Carlow Stables, which was located at what's now the corner of the entrance to the Nicholastown housing estate, acted as a staging station. Fresh horses from the stables were used to replace exhausted ones, on the long-distance Bianconi coach route that ran from Dublin to Cork, via Clonmel. In later years, the building was used as a location for staging plays and dances. However, no photos of it seem to exist.

The Carlow Stables were located at what's now the corner of the entrance to the Nicholastown housing estate.  Image courtesy Tailte Éireann.

Anyone Know Anything About the Hideout Pump?

Pump outside Hideout pub. Image courtesy Google Maps.

Do we know anything about the well under the pump near The Hideout? Imagine if it was made a feature, internally illuminated and with a walk-on, structural glass, see-through cover? (I think they did this with a well that was discovered in the square in Kildare town). How wide or deep is it? Maybe it's just a narrow shaft, but I would have thought these wells were dug by hand in the 19th century and lined with stone or brick. So it would have had to be at least wide enough to use a shovel and pick axe comfortably. The first edition 6" OSI map from c. 1837 doesn't show pumps, but the 25" map from c. 1900 shows them marked with the letter "P" in several locations in the town: One at the Carlow Stables just before the entrance to the Nicholastown housing estate, this one at The Hideout, in Bardon's yard, another one behind Liffey View House on the hill and yet another just before the cottages at Hillside.

I presume the reason knobs were removed from "fountains" (which were connected to the mains supply) and handles from pumps (or the linkages removed internally) was due to health and safety concerns. From what I recall, the pump at Harristown was still working in the 1990s. what about the one in Mile Mill and Brannockstown? 

 

Map image courtesy Tailte Éireann

High Volume Releases at Golden Falls Dam

Golden Falls dam, Ballymore Eustace. © Eugene Brennan

According to the ESB, a flow rate of 15 m³/s (cubic metres per second) is estimated for today, 13th November, from 00:00 to 24:00. That's 15 tonnes of water per second. The compensatory/buffer lake at Ballymore Eustace has risen by 9 m since 14th October. The lake acts as a buffer to cater for larger releases at the Poulaphouca dam. I'm guessing some of this water may be through the sluice gates and over the spillways, if the water has reached "overflow" level, rather than through the penstock (a large diameter pipe) feeding the alternator. I've put in a query to the ESB, requesting answers to some technical questions.

The Golden Falls hydroelectric power station has a single three-phase alternator that generates 4 MW of electrical power. For comparison, onshore windmills typically output 2 to 3.5 MW.

How to Lubricate a Bicycle Chain With Candle Wax

Waxing a chain. © Eugene Brennan

Instead of oil, I've been using church candle wax for lubricating my bike chain over the last year. They were throwing out the waste-ends of candles from the church and they were given to my mother, possibly because she knew I was making candles at the time. That's probably almost 20 years ago. I was experimenting with using PVC waste pipe as moulds for casting the candles. Anyway the process of chain waxing is somewhat tedious, but worth it. Before dipping in wax, I rinse the chain five times in kerosene to remove all grime and then the final rinse is in methylated spirits to remove kerosene.

Chain washing kerosene. © Eugene Brennan 

 

Washing the chain in kerosene. © Eugene Brennan

 

The next stage is to dip the chain in hot wax, melted for safety reasons in a double boiler. This ensures that the wax can never reach more than 100 degrees Celsius, well below its autoignition temperature.

Chain waxing has to be done every 200 to 300 miles. However, this makes the chain nice and clean to the touch, and grit from the road doesn't stick to it and wear it away. So far, I've got 1200 miles out of a chain with waxing and there's minimal wear (I'm nerdily logging the data on a spreadsheet), This isn't much by road bike standards (it's on my MTB), but I was getting less than 1000 miles I think before because of all the grit that stuck to the oil and rapidly wore the chain.

 

Double boiler for melting wax safely. © Eugene Brennan

Melting candles. © Eugene Brennan

Golden Falls Generator Assembly

Golden Falls G 4 assembly. Main shaft guide bearing and oil pump. July 1948. 

Permission to reproduce image courtesy ESB Archives.

 © ESB Archives

ESB Archives have sent me some photos, dating from the 1940s, of the electrical generating equipment in the Golden Falls hydroelectric power station. The stator assembly of the generator can be seen around the perimeter of the casing in two of the photos. Similar to the alternator in your car, a rotor carrying field coils, driven by a shaft from the turbine, turns within the outer stator. The field coils are excited by DC to create a magnetic field and three-phase AC is drawn off the stator. (The same thing happens in a car alternator, but the three-phase AC at a frequency of several hundred hertz is rectified to DC. Older cars used dynamos, that produced DC directly, but suffered from several drawbacks).

Anyone Got a Good Nose?

 Image courtesy Google Maps.

The smell that was present last year, adjacent to the entrance to Kilcullen Business Campus, has returned. It might be gas or sewage, I'm not sure. It could be sewer gas released from a vent.
There's a mark on the road surface, extending from one side of the road to the other, where it was re-tarmacked after a service was laid. So that may be where the gas or sewer line runs under the road. The smell is coming from the area where this service enters the business campus, behind the timber fence to the right of the main gate.
My sense of smell has deteriorated because of COVID, so maybe someone could confirm if the can smell anything?

I'll have a look at the Gas Networks Ireland map to see where the gas line enters the site. I rang either John Craddock Ltd or Murphy Geospatial last year, can't remember which, to enquire whether there's a management company for the business campus. But I was told there isn't.

Is it council owned?

Another possibility is that there's a sump (a holding tank, that acts as a reservoir for sewage until the sewers can take it) near the entrance and this has a vent that releases sewer gas, just like a septic tank.

Gas Turbine Engines

Types of gas turbine engines. Created by ChatGPT.

Gas turbine engines are used in many applications, not just on aircraft. They power ships, tanks, helicopters and they're also sometimes used in power stations to drive alternators (AC generators) for generating electrical power. Gas turbine engines have been used to power trains in the 50s and 60s, e.g. the Union Pacific GTEL locomotive. A "jet engine" is a specific type of gas turbine engine where a jet is used to provide thrust. The jet can provide thrust directly (turbojet) or power a fan (turbofan engine) or propeller (turboprop). The advantage of a gas turbine engine is its high efficiency when scaled up and run at high power. At small scales (if they were used to power cars) they would be less efficient than a piston engine. Gas turbine engines also have a high power to weight ratio compared to a piston engine.
Thanks to ChatGPT for drawing a graphic for me. 

Nice New Wheels Delivered!

Sealed bearing wheels. © Eugene Brennan

It took me forever last week to source these. The engineering aspect and excuse to post about them is that they have sealed ball bearings, so somewhat better than the cup and cone bearings used in traditional mountain bike wheels. The latter are a pain in the arse to maintain and water gets into the ones on the back wheel when hosing the sprockets after they get covered with muck. So they have to be dismantled, cleaned and degreased (see photo below). Several local bike shops hadn't heard of these wheels or said they didn't exist. Anyway 360cycles.ie will be getting a good review because they were really helpful and gave lots of updates on the progress of sourcing them for me.

Sealed bearing image public domain, courtesy 4volvos.

Components of a rear cup and cone bearing. © Eugene Brennan

Clock Drive Rotor

Wall-clock rotor (approximately 8 mm long). © Eugene Brennan

The mechanism (also called the movement) or working parts in a quartz battery clock is a bit simpler than in a traditional wind-up clock.

At the heart of the clock is a quartz oscillator, which generates a pulse every second. An oscillator is a device that does something regularly, like a pendulum that swings back and forth, a tuning fork vibrating, a string on a guitar or the air in an organ pipe. All these are mechanical oscillators, but there are also electronic oscillators.

An electronic oscillator generates a voltage signal that repeats itself at a set frequency. In the case of the oscillator in a clock, this runs at several thousand hertz or cycles per second. An electronic component called a quartz crystal sets the frequency of the oscillator to about 32,768 Hz with a high degree of accuracy. The frequency is divided down and reduced so that it eventually becomes 1Hz or 1 cycle per second. The output of the oscillator drives an electromagnet that acts on a tiny magnetic rotor, flipping it half a turn every second. The rotor has gear teeth that mesh with a train of other gear wheels and this eventually turns the hands of the clock.

Quartz clock mechanism. © Eugene Brennan

A closer look. © Eugene Brennan

Technology Tedium

AI image generated by Grok.

A guy I was in school with was typing in the code for a game and after spending ages at it, his kid brother pulled the plug on the computer before he had it saved to cassette. I don't even think of saving work now until I'm completely finished, although I should, in case there's a glitch. When a laptop is put to sleep, everything resumes when it's woken up again. And we have undo buttons in applications for reversing anything we've done. Many applications that ran on MSDOS, before Windows, didn't have an undo button. So if you were typing a document or drawing something, you had to save to file before you made any major changes so you could reload and get back to a version before the change.

Extinct Infrastructure in Kilcullen

Image courtesy Google Maps.

I've always been fascinated by infrastructure and utilities such as electrical and plumbing systems. When we were in senior infants, I remember Richard Brophy, a classmate, and I lifting manhole covers in the yard of the old girls' school, which is now the parish centre. Maybe this was one of our chores to make sure the drains weren't blocked or else we were just curious. In any case, the nuns would have been hidden away in their "hut" at lunch time, unaware of what we were up to. Hosing out the toilet block in the old boys' school, which wasn't much cleaner than a cow shed, would be a weekly chore in years to come. A more pleasant job in 6th class was being sent around all the classrooms to collect the contents of the waste paper baskets and then lighting a huge bonfire against the wall of the briquette shed— all unsupervised, but great fun. I wondered as a child about the object shown in the photos above. In the early 70s, it was a green, cast-iron pipe, sticking out of the ground, possibly with a certain amount of decorative detail. In modern times, infrastructural components such as lamp posts tend to be purely functional, but in the past, they were often ornately designed — for example some of the poles that once carried Dublin's overhead tram wires have now been repurposed as lamp posts. The pipe in the photos was still extant in 2009 and covered in ivy, but disappeared when the boundary wall of CPC was rebuilt. It was presumably a sewage vent, which became unnecessary for a reason I'm unsure of. Vents like this are used in domestic plumbing systems to allow air into sewerage systems to prevent water from being siphoned out of S and P-traps and to allow wastewater to flow freely.

Megalithic Mound or Natural Glacial Deposit?

Image courtesy Google Maps

I've often wondered about this area of raised ground and whether it's a megalithic feature. The ground rises gently on all sides, but the high ground isn't overly symmetric like other man-made megalithic sites in the landscape. It doesn't appear in any archaeological records. As kids, when we were looking for the legendary tunnel that ran from New Abbey to the Valley Park, I remember investigating a hole in the slope of the mound, lined with stones. Maybe it was the remains of a well? Does anyone remember this?