Archive for the ‘Science’ Category

The speed of cars vs. wildlife

31 December 2012 Leave a comment
2012-10-06 21.00.24

‘So did the deer just bounce off and limp away?’ – Erm no, most definitely not..

Gutted. We hit a deer on the way to a night out in Peterborough (which was actually a great laugh – the night out, not hitting the deer) and smashed up all the front nearside of the car. Grrrrr..

If anyone knows the A605 between Thrapston and Peterborough, they’d know it’s a fast, barely lit road that runs through a large area of rural countryside. We were shooting along it at about 70 mph and this thing shot out of the darkness, slamming straight into the front nearside (the left of the car as you’re sitting in the driver’s seat) before I could react and brake (good job really as I may have over-reacted and skidded off the road, maybe..).

This prompted the car to do a tiny little bunny-hop followed by the noise of plastic and metal dragging on the road and breaking into a hundred tiny little pieces. My wife, bless her, thought it was the deer making this noise (the crunching of bones) and burst into tears!!

It was far too dangerous to stop there and then so we limped on to our destination and checked the damage (the pound signs were flashing in my head thinking about repair costs).

Little kamikaze bugger had wrecked the front of my car! A big hole under the front pumper, power steering  had stopped and the washer fluid reservoir had started to drip out all its contents onto the tarmac below.

Later when telling my mum about what had happened she piped up ‘So did the deer just bounce off and limp away?’. ‘No Mum. Most definitely not!’. We were going far too quickly for it to survive.

Which got me thinking – what speed were we going in meters per second? And what chances did the deer have??

The Yahoo! Answers green smiley.

The Yahoo! Answers green smiley. (Photo credit: Wikipedia)

So being the sad sap that I am, I worked this all out with a lot of help via Yahoo Answers from a user called electron1 who provided a great answer:

  1. 70 mph is about 112 kph.
  2. So 112 kph is 112,000 meters per hour.
  3. There are 3600 seconds in an hour (which is 60 secs x 60 mins)
  4. 112,000 meters divided by 3600 secs (or approx 112 divided by 4 if you’re doing it in your head)
  5. = 31.1 meters per second (28 with the rough method)

So we were travelling at approx 30 meters per second (ms^1) when we hit this deer.

So what were it’s chances of surviving?

To determine the acceleration and force on the deer, we need to know the amount of time which passed as the velocities changed.

Let’s assume that the collision occurred during a 2 second time period. So t = 2.

  • Acceleration = (vf – vi) ÷ t.

Where vf is final speed (30 ms^1 in our case – I’ve disregarded the change in momentum to the car after hitting the deer as it’s so small) and vi is initial speed (0 as the deer was stationary when we hit it).

  • So the acceleration of the deer = (30 – 0) ÷ 2 = 15 m/s^2

To find out the forces involved we use f = ma, where f is the force, m is the mass and a is the acceleration.

We know the m if the deer is 10kg and the acceleration as above is 15 m/s^2

So f = 10 * 15 = 150 N (or Newtons)

So what does 150 N compare to?

For example, is it more than gravity?

Gravity is acceleration, not a force. Weight is the force, which is caused by gravity.

  • Weight = mass * g, g = 9.8 m/s^2
  • The acceleration of the deer, 15 m/s^2

So yes, the acceleration of the deer was greater than gravitational acceleration.

They’ve investigated boxers and found they can generate up to 5,000 newtons of force with a punch. Whilst kicks can produce up to 9,000 N! also has the below different orders of magnitude of force:

Magnitude Value Item
newton (N) 1 N The weight of an average apple
10 N 9.8 N One kilogram-force, nominal weight of a 1 kg object at sea level on Earth
102 N 720 N Average force of human bite, measured at molars
103 N
kilonewton (kN)
8 kN The maximum force achieved by weight lifters during a ‘clean and jerk’ lift
9 kN The bite force of one adult American alligator
104 N 18 kN The bite force of an adult great white shark
45 kN The force applied by the engine of a small car during peak acceleration
105 N 100 kN The average force applied by seatbelt and airbag to a restrained passenger in a car which hits a stationary barrier at 100 km/h
890 kN Maximum pulling force (tractive effort) of a single large diesel-electric locomotive
106 N
meganewton (MN)
1.8 MN Thrust of Space Shuttle Main Engine at lift-off
1.9 MN Weight of the largest Blue Whale

What does all this mean? After all 150 N seems very little compared to the examples above.

I’m not entirely sure. Please leave me an example if you can shed more light on all this.

And beware of kamikaze wildlife!

Big big BIG numbers: googols, centillions and googolplexes

1 July 2012 4 comments

Numbers numbers numbers...“I love you one hundred million times” – says my 3-year-old daughter to me.

“(lol) Well I love you 20 thousand trillion times more!” – Me back to daughter whilst thinking, ‘well what is after a trillion anyway? Hmm..’

I know the below stuff is on Wikipedia (which is where I got it all from) but I’m guessing not many people have actually thought to (or bothered to?) learn what comes after a million – billion – trillion – etc etc.

So in true QI fashion let us ponder this ‘quite interesting’ stuff and go through the names of some stupidly-massively-huge numbers. All in the name of learning something new that you may not have ever thought to before!

Names of large numbers

The first thing to realise is that the UK and the US have got a different naming system to continental Europe (not sure what places like Canada and Australia do – probably the same as the UK/US I’d imagine). So for example in Europe they call 1,000,000,000 a Milliard, whereas in the UK/US we call it a Billion. Their Billion which follows that is our Trillion, and so on).

  • I’ll just stick to the UK/US naming convention.
  • The Short Scale depicts how many 0’s there are after a 1, – so for example 1 Million is 1,000,000 (or 106).
  • In practice the below terms aren’t really used. Instead it is simply read out “ten to the forty-fifth” which is just as easy to say, easier to understand, and less ambiguous than “quattuordecillion” (which can also mean something different in the long scale and the short scale anyway!).
Name (UK/US naming) Short scale
Million 106
Billion 109
Trillion 1012
Quadrillion 1015
Quintillion 1018
Sextillion 1021
Septillion 1024
Octillion 1027
Nonillion 1030
Decillion 1033
Undecillion 1036
Duodecillion 1039
Tredecillion 1042
Quattuordecillion 1045
Quindecillion (Quinquadecillion) 1048
Sexdecillion (Sedecillion) 1051
Septendecillion 1054
Octodecillion 1057
Novemdecillion (Novendecillion) 1060
Vigintillion 1063
Centillion 10303

So you see it’s actually fairly simple and goes up Bi-, Tri-, Quad-, Quin-, etc etc. All latin-based words. On this University of North Carolina webpage they discuss another Greek-based naming system, though this is highly unlikely to ever be adopted!

So what of the bigger numbers?

  • A Googol is 10100 (which Google famously takes it’s name from via a misspelling).
  • A Googolplex is 10Googol (which a chap called Carl Sagan estimated that writing out in standard form (i.e., “10,000,000,000…”) would be physically impossible, since doing so would require more space than the known universe provides!).
  • Nothing however is as large as Infinty, which is a nice catch-all really for ‘one more than you’.

Further links

The Thesis Whisperer

Just like the horse whisperer - but with more pages

ukmade - UK Made Products - BRITISH MADE

Made in Great Britain - recommendations of quality products made in the British Isles - Made in the UK


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