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**The following maths is suitable for Year 9+**

**but can be presented to lower grades just to show**

**maths is cool!**

Just another WordPress.com weblog

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**The following maths is suitable for Year 9+**

**but can be presented to lower grades just to show**

**maths is cool!**

**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 2020, **according to the annual, independent Global Drug Survey**, Australians were drunk more often than any other country in the survey. Melissa Cunningham reported in The Age (**How to cure a hangover!**, 11 DEC 2021) that Australians admitted being drunk 27 times a year, compared with the global average of 15.

Naturally, a lot of this drinking takes place during the Christmas holidays or the Silly Season. Unfortunately, it appears to be the SILLY SEASON all year round in Australia.

Data from 32,022 people from 22 countries were used in the preparation of this Global Drug Survey

**For binge drinking stats**

**See Dangerous Maths: Young, drunk, dead.**

LINK: **National Drug & Alcohol Research Centre data**

- UK 15-34 years for 2011. Source
- Australia 15-24 years average Source
- CANADA Under 18 years of age. 1996 It is believed that as many as 83 percent of teenagers in Canada consume alcohol. Back in 1996, underage drinking was responsible for 3,500 deaths and 2,000,000 injuries. A 2002 survey found that 20 percent of eight graders had consumed alcohol within the previous month. Source
- USA. 4,358 people under age 21 die each year from alcohol-related car crashes, homicides, suicides, alcohol poisoning, and other injuries such as falls, burns, and drowning. Source

Sensitivity to caffeine varies for individuals, but in healthy adults the half life for caffeine is approx 6hrs meaning your body eliminates half the caffeine you have drunk in 6 hrs. Ref: **Caffeine Pharmacology**

Caffeine interferes with sleep. **One study** found that consuming caffeine **6 hours** before bedtime reduced total sleep time by **1 hour**.

Caffeine content sources **Caffeine Content Data Base**

Street art by **JEKS**, South Carolina

The Half life equation is an exponential function.

The **Mayo Clinic **advises up to 400mg Caffeine a day for adults, which would be;

10 black teas

7 instant coffees

4 cappuccinos

2 dark roast brewed

less than one cup of Black Insomnia Coffee.

Approx half this amount of caffeine for 14 yos.

**USE The Random Number Spinning Wheel HERE**

**Here’s Mathspig’s Play List with links:**

1. Angie McMahon, Melb, AUS **Pasta**

2. San Cisco, WAust **Skin**

3. Go Get Mum, Melb, AUS **Phone, Key, Wallet**

4. Shirley Kovacs, Netherlands **Sound of the Underground**

5. The Teskey Brothers, Vic **Hold Me**

6. The Dead South, Canada **In Hell I’ll Be in Good Company**

7. The Staves, UK **The Long Run**

8. Cat Clyde, Canada **Mama Said**

9. Mojo Juju, Melb, AUS **Train Along the Hawkesbury**

10. Marlon Williams, NZ **Hello Miss Lonesome**

11. Syzygy, Melb, AUS **The Pendulum**

12. Vampire Weekend, USA ** ****Harmony Hall**

**Deep Purple: The Loudest Rock Band Ever**

**Lime Cordiale, a popular band in Australia**

**Find dB answers here.**

**I am grateful to Jeff Jacoby and his column, Arguable, in the Boston Globe for reminding me of how Isaac Newton filled in his time when he went into self-isolation during The Great Plague of London in 1665-1666. **

**He spent time thinking and the results were astounding!!!!!**

The following equation went viral on Twitter like the Yanni & Laurel sound Tweet. What answer do you get?

**The Equation that tried to stump the internet!** New York Times