## 2. I’ve got a BAD maths Teacher: BUSTED…………………………………………………………………………….

## 3. Everyone Hates Maths Anyway: BUSTED

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## 4. Too many different ways to do the………..

## same thing: BUSTED

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**According to the fab NBC video, Mathletes, nine Figure Skating judges score competitors for the complexity of each element (eg. Triple axel or triple spin jump) and the quality of the performance producing a score out of ten.**

**Tessa Virtue and Scott Moir win GOLD at Pyeong Chang 2018**

This is a typical figure skating score card for one competitor.

The final score, however, is based on the average for only 5 of these scores. Two are eliminated by random selection (Red Brackets). Then the top and bottom scores are removed and the remaining five scores averaged.

Four scores are removed. Two by the random selector (in brackets) and then the top and bottom scores (with line drawn through them)

Four scores are removed. Two by the random selector (in brackets) and then the top and bottom scores (with line drawn through them). But this time the random selector eliminates two low scores.

The average:

Same score cards but Skater B gets a higher average score than Skater A.

Skater A is, in fact, beaten by a random number selector!!!!

]]>**While air resistance has little impact on aerial skiers it is a significant factor used by ski jumpers to increase their jump distance.**

**The significant maths for ski jumpers is therefore X-section area.**

**Here is the jump at Pyeong Chang, 2018. Just imagine going down that at top speed!!!**

**Ski jumpers increase their speed going down the ramp by reducing their X-section area:**

**Once they leave the ramp, ski jumpers try to increase their X-section area like Ski Divers to slow their vertical fall. But they have to land safely so they keep their skis at a minimum angle.**

**Here is the formula for Air Resistance of Drag:**

*D *= ½*CApv ^{2}*

**Where C is the drag coefficient or constant, which depends on the shape and spin of an object. It is found by testing the object in a wind tunnel.**

*A* is the X-section Area,

*p* is the density of the air and

*v* the velocity of the object.

**More here.**

**As Abby Hughes has tripled here X-section area in the air she will ****have tripled the vertical drag during her jump. This will slow here decent.**

*Mathspig calculated the X-section area by the old fashioned method of counting squares and rounding off the final count. Mathspig sized the two pics of Abby Huges so that her head was the same size in both pictures.

]]>**Here is the sensational pairs team from the 2018 Winter Olympics.**

**But why do ice skaters spin so fast?**

**Here is the math!**

Well, mathspiggies, the girl in this video is right. Angular momentum remains constant unless external forces are applied.

L = angular momentum

v = linear velocity

r = separation of object

Let’s have a look at this equation:

The fastest spin on ice skates was achieved by Natalia Kanounnikova (Russia) with a maximum rotational velocity of 308 RPM (rotations per minute) at Rockefeller Centre Ice Rink, New York, USA on 27 March 2006. See Guinness Book of Records.

Other spins include:

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Skaters can spin faster during a triple axel jump because there is no friction from the ice slowing their spin.

To complete a quad axel, it’s estimated that the skater would have to rotate in the air at:

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More info here.

Now, mathspiggies, you must separate Linear Velocity (v_{1} ) from Angular Velocity (v_{r} ). Linear Velocity is measured in m/sec ie. it is the speed of, say, a skaters foot around the circle. Angular Velocity is measured in either RPM (Revolutions Per Minute) or degrees or Radians per minute. Ie. It is the rate of spin. We can’t judge how many m/sec a skaters foot is moving in a circle. We can only see how fast they spin. In other words, we see their Angular Velocity. When a skaters foot is in the Camel position that foot travels in a very big circle.

But when that same foot is in a Triple Axel postion it moves in a very, very small circle.

By halving the radius, firstly, a skater’s Linear Velocity doubles due to the conservation of angular momentum.

Then, secondly, by halving the radius the circumference of the circle moved by , say, the skaters foot is halved.

Overall, by doubling the velocity around the circle and halving the circumference a skater increases their rotational velocity by a factor of 4.

Look at the numbers:

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That’s about right.

]]>**In 2014 Winter Olympics Annette Gerristen (below) lost the Gold Medal in the 1000 m Women’s speed skate competition by 0.02 seconds.**

**Italy’s Arianna Fontana wins the 500 m Speed Skating 2018 Olympic Gold Medal in 42.569 seconds ahead of Yara van Kerkhof of the Netherlands and Kim Boutin of Canada. **

**Apollo Ono (below) competed in the 1500m men’s speed skating. He has won 8 Olympic Medals.**

**If a speed skater lost the Gold Medal by 0.001 seconds, the smallest measured time segment at the Olympics, they would be:**

**behind the winner. That is less than the length of a small fingernail.**

Aerial skiers aim for height rather than length. Their aerial flight times are much smaller than ski jumpers so air resistance has minimal impact.

In fact, there is one law the aerial skiers cannot break. It is the law of gravity.

Here is an equation for projectile motion from Wired magazine.

The equation for projectile motion also applies to **Motorbike Jumps** and **Longbow Arrows**.

Here is the x-y graph for different launch angles.

You can go to this page for complete calculations. Aerial skiers twist and turn but their CENTRE OF GRAVITY must follow this graph. More on centre of Gravity at The Great Back Pack Attack ie.

The centre of gravity of Aerial Skiers must follow a

**The average age of the 60 years of FORD vehicles here is 30 years. MODEL NAMES at end of post.**

**I did this to show that averages can tell us a lot or, in this case, not very much.**

**Here are some averages that tell us a lot about different countries and their love of cars!**

**The average age of vehicles in USA is a record-high of 11.6 years. More here.**

**Car ownership rates data here.**

**This is the average vehicle age, which includes vans and utes. Almost 1,000,00 vehicles were scrapped in 2015-16. More than 30% of vehicles are less than five years old. Data here.**

**In 2016, the average age of vehicles on Canadian roads was 9.66 years. Data here.**

**The average age of cars in UK is 7.7 yrs. some interesting stats here.**

**The average age of vehicles in New Zealand is 14.3 years. The average age of trucks and buses is over 17 years. Data here.**

**Cars in the European Union are on average 10.7 years old. Data here.**

**The average age of vehicles in Poland is 17.2 years. Daata here.**

**The average age of vehicles in Romania is 15.3 years. Data here.**

**The average age of vehicles in Greece is 13.5 years. Data here.**

**Ethiopia has the lowest car ownership in the world with 2 per 1,000 inhabitants in 2014.**

**The average age of Ethiopia’s fleet is 15-20 years. Best guess! Data here.**

**More deaths occur due to falling off chairs in Australia. Quad bikes are deadly anywhere. **

**Full Stats and references here.**

**Meanwhile, you see a shark fin. You can swim BUT what distance do you need to be from the shark to make it to the beach.**

**You will find some interesting maths here.**

**Some survival tips at the above link.**

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**1a. The WORLD POPULATION as ONE BIG CROWD … METRIC**

**1b. The WORLD POPULATION as ONE BIG CROWD … USA Units**

**2a. If all the cars in the world were parked together what area would they cover? Metric Units**

**2b. If all the cars in the world were parked together what area would they cover? USA UNITS**

**3. If you put the population of the world into AUSTRALIA what area in m ^{2} would we get each?**

Meanwhile this Mathspig blog is full of AMAZING middle school maths such as:

**HOW MUCH BLOOD CAN YOU LOSE AND SURVIVE?**

**WHAT VOL OF ALCOHOL IS LETHAL FOR TEENS?**

**THE TERRIFYING MATH OF RUNNING FROM A BEAR USA UNITS**