Any question answered...

Maybe a daft question, but do you need to use the laptop at all?

Yeah I do I present all sorts of shit and run workshops.

Here's a thing that's driving me insane. My wonderful neighbour opposite is unintentionally breeding pigeons under his solar panels. They've steadily increased to about 28. As a consequence some roost on my roof which wouldn't be a problem but for the fact that I sleep in the loft conversion. From sunrise I get them stamping about on the flat roof section and taking turns to slide down the Velux windows. Apart from rapid lead poisoning, which my daughter has bitched about, what can I do to get rid of them?

https://youtu.be/yhuMLpdnOjY

Take up falconry as a hobby.

shit and run workshops

How do I sign up?

Reasonable option.

Sounds stressful. I stayed at an Airbnb once with pigeons stamping on the roof every morning, sounded like someone knocking frantically on the window/door.

Don’t know the name but those area denial sticks they use around CCTV cams at train stations might work. You could put a strip on the flat section or somewhere along their descent route so they can’t slide down.

Could also get a cat, furry little psychos.

Ah well, we have a cat but she's 16 with failing kidneys and for the last four years has been doing a good impression of a Manx cat. I think shoving her out of the Velux window to scare the pigeons away may finish her off

How can I calculate the work necessary to move .05kg over 55km in one hour? It’s driving me up a wall, especially knowing it’s not complicated but I just don’t see it.

55 km horizontally in a vacuum? Zero work done.

55 km horizontally in not a vacuum? You need to know wind resistance of your object, and the speed it moves, and so on.

Thanks for replying. I’m trying to work out the energy impact of using normal inner tubes vs. light weight inner tubes (combined weight difference of 50g) on, e.g., Campenaerts’ hour record of 55km. It’s for illustrative purposes rather than a formal inquiry, so don’t need to overly complicate it.

Edit- what I’ve done so far:
W=F*d
W=(m*a)d . I’m not sure how to work out or around the acceleration.
W=[m(v-v0/t)]d
W=[.05kg(15.28m/s-0m/s /3600s)55000m
W=[.05kg(.004244m/s^2)]55000m
W=.000212N*55000m
W=11.66J
...?

For that case, the mass is all but irrelevant, but the thinner walled tubes will have smaller hysteresis loss if made from the same material. That effect will massively overdominate any effect from the difference in mass.

Depends on your path round the velodrome, doesn't it? If you're managing a steady speed round the track and not going up and down the banking, the only difference is going to be in the initial work of accelerating up to speed.

I would have thought that on a track it was the reduced rolling resistance of lightweight tubes that made the greater difference (and wouldn't they have used tubs?). Rolling resistance is also a function of load on the tyre, but a 50g difference is going to be an infinitesimal effect at track pressures.

(Edit - beaten to it by Tester)

Cheers @gbj_tester and @Thrustvector.

50g is about a large mouthful of water or the reduction in weight from an Dura-Ace component to a 105. I was curious to work out the actual impact in energy expenditure of a reduction in the mass moved by the rider. More complex a question than I reckoned.

To a first approximation, unless the ground is going steeply uphill, any small change in weight is dwarfed by changes to rolling resistance and aeros. There's a reason the UCI quickly banned recumbents, despite most designs being significantly heavier than diamond-frame uprights...

If you're managing a steady speed round the track and not going up and down the banking

There's an interesting thing here for more advanced maths illustration. Leaving the inner tubes aside, because they are nothing like a simple change of mass, let's say the initial sample bike comes in at 6.75kg. To pass scrutineering, you buy a 50g slug of Tungsten and glue it inside one of the frame tubes. On a pursuit bike, where do you glue it to maximise the benefit?

unless the ground is going steeply uphill, any small change in weight is dwarfed by changes to rolling resistance and aeros

Also the reason I recommend people work on their bike fit and aero profile before dropping £££££ on the lightest components.

Edit because I was reminded of this scene https://m.youtube.com/watch?v=P-hUV9yhqgY

I can bullshit rationales for a number of locations, but can't decide what the magnitudes of the effects would be. Purely on the ∆h of the mass I'm going to guess at the rear dropout?

can't decide what the magnitudes of the effects would be

The magnitude will be small whatever you do.
I'll hold off on giving my opinion just in case anybody else feels like weighing in with ideas.

1. Are there any free parametric modelling programs worth using. I can't make the switch to direct modelling ala sketchup.

2. Are there any 4 gang extensions with 4ish USB ports which won't burn my house down. Or should I just buy any extension and a multi port USB charger.

Oops, meant to say 'relative magnitudes' there. Also assuming that this is a UCI-compliant answer, such that 'turn it into a fairing' would get you on the naughty step.

just buy any extension and a multi port USB charger

This

Fusion360 is parametric and free for home gamers and students.

Also assuming that this is a UCI-compliant answer

It's a "physics problem" answer, so the ballast goes inside the frame where it can have no effect on the aeros, and the glue is both massless and infinitely strong and rigid, so the spherical(d=17mm)ballast can neither move, despite the single point contact, nor affect the structural properties of the frame.

In the seat tube above the bottom bracket