An unfun sleepless night. Caused by my brain still working when my body wasn’t interested. It’s surprising what goes through my mind when I’m trying to sleep, usually about twenty work related threads. It does mean I get quite a lot of work done, well the theory of it at least, but it also means I’m fairly knackered in the morning. Took the dog to daycare at 6:15.

So today was mostly about springs and air again. First was setting up an anti-roll bar, that was fairly straight forward. Then it was on to aerodynamic wings, which turned out to be more straightforward than I thought it would be. Basically for a simple wing you just have the area the angle and a couple of coefficients, one for drag and one for down force. You then just multiply that by the square of the air velocity and the air’s mass and you’re done. Well you’re done in so far as you have a force, you then apply it at the wing attachment point. Doing something not really physics related tomorrow, which will make a change.

The cleaners came, they were hear for about an hour an ten minutes, I’m sure I pay for more than that. They didn’t do a very good job. I’ve sent an email, they will get their marching orders as I haven’t had a reply. I’ll give him to the weekend.

Picked up dog.

Did some more Japanese, almost at the end of unit five now. Diluted the new wine kit, just waiting for it to come up to temperature now which will be tomorrow probably, then I’ll get it going.

Started off the day thinking it was a Monday, meaning it was pretty slow going. Anyway, sorted out an issue which I then found out actually wasn’t so ended up reverting it. Then implemented rolling resistance, which is basically just a coefficient of the downward force. So the harder something is forced into the ground the more resistance it gives.

Took the dog out for a run as it was really nice weather, still very cold, but the sun was out. It’s the first time we’ve done that in months. It was fun but she does slow me down quite a lot, but will give it ago again if the weather is nice.

Then came back to do aerodynamic drag. Now this is quite interesting, aerodynamic drag is the force an object is subjected to when its travelling at a velocity. The faster the object, the more the drag. The drag can build up and be a very important force as it’s actually the square of the velocity multiplied by a coefficient. So rolling resistance is important up to a certain velocity and then aerodynamic drag takes over. So what is this magic force? Well it’s actually the weight of air. So what’s the weight of air? Well first a distinction, weight and mass are not the same thing. Weight is actually mass under the force of gravity, so w=mg where m is the mass and g is the gravity. Gravity is normally taken as 9.8 or 10 for simplicity, it’s an acceleration so it’s units are meters per second per second or ms^-2. So anyway, back to air, what’s it’s mass? Well this actually depends on air density or how close the particles are together and this depends on temperature. So air at about 15 degrees centigrade is about 1.2 kilograms per meter cubed, which when you think about it is quite heavy. So no wonder when you drive a Volvo at 100Mph the aerodynamic drag is quite a force to be reckoned with.

Did another Japanese lesson, it’s getting very tricky and got a bit tired towards the end.

Got up, which wasn’t quite a big a challenge as it normally is on a Saturday, not sure why. Walked the dog. Took her to the vet, her weight is coming down nicely now. Tried to find people in so I could do some more re-checks. Only managed one fairly old cat (the owner answered the phone, not the cat).

Did the shopping. Went into town, failed to buy anything. Went to mothers, via the cat check. Delivered to her, two bottles of wine, an electric blanket and a dressing gown. Obtained, five empty bottles of wine, some spicy nuts, some bake shake stuff and a fruit cake. a fair exchange is no robbery.

Came back and did the accounts. I had a statement from one of the long term investments from Sun Life. In thirteen years I’ve made an average of 1.7% a year. In today’s markets that’s actually probably quite good. Going back all those years though it probably isn’t. Anyway I’ll give it another thirteen and see if they improve.

Bath and curry time (in that order, but not at the same time). Sarah’s tomorrow, so take the dog out first thing.

Working heavily in two areas I really don’t like, physics and maths. Which is surprising as I’m pretty good at both physics and maths. Spent the day basically trying to find out why a flat object travelling a couple of centimetres above a completely flat surface was randomly bouncing in the air. It turns out after god knows how many hours they are touching, this is because the physics library we are using has a margin of 4cm’s. This means any two surfaces which are within 8cm’s of each other are actually randomly touching. Great. Managed to sort some of it, but it’s going to be a real pain I just know it.

Went for a run again. Picked up the dog from doggy daycare, she is now asleep on the couch next to me. I’ve been doing research into springs, exciting evening for sure. Did a little bit of Japanese but didn’t get beyond writing down the new words on flashcards. I’m owed time again so will do a session tomorrow morning.

Today I fixed a couple of issues I was having yesterday. Actually I fixed something I had spent several hours on yesterday in about five minutes this morning. As usual though, you fix one problem and another one come along. I hope that one takes five minutes tomorrow morning. It’s to do with constraints, they just aren’t working how I want. I don’t really want to use them at all but looks like I will have to.

Finally went out for a run, which is the first time in almost a month due to the worlds longest cold. That, thankfully has now almost vanished. Jamie still has some sort of sinus infection.

I did some more Japanese, finished unit 4, so 6 units to go before we set off. Well that’s the plan anyway.