## FOR THE LONGEST KICK or THROW in Football you need this MATHS

April 19, 2022

………………………………………………

The following maths is suitable for Year 9+

but can be presented to lower grades just to show

maths is cool!

## Winter Olympics 2022: Why do figure skaters spin so fast?

February 3, 2022

Here is the sensational pairs team from the 2018 Winter Olympics.

But why do ice skaters spin so fast?

Here is the math!

# REASON  1:

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

# L = mvr

L = angular momentum

v = linear velocity

r = separation of object

Louisa Barama, USA

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.

## Record spin :  vr = 308 RPM

Other spins include:

Mao Asada, Japan, triple Axel

## Triple Axel spin vr = 220 – 280 RPM

……………………………………………………………………………………………..

## Maximum Triple Axel spin vr = 402 RPM

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:

## 540 rpm.

…………………………………………………………………………………

## Camel spin vr = 90 RPM

More info here.

Kim Yuna, South Korea

# REASON 2:

## a camel spin into a very fast standing spin?

Now, mathspiggies, you must separate Linear Velocity (v1 ) from Angular Velocity (vr ). 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.

Patrick Chan, Canada, Camel Spin

Patrick Chan, Canada, Triple Axel

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:

## Camel spin vr = 90 RPM

…………………………………………………………………………………

## Triple Axel spin vr = 4 x 90 RPM = 360 RPM

That’s about right.

## Young, drunk, dead: How the silly season kills!

December 13, 2021

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.

1. UK 15-34 years for 2011. Source
2. Australia  15-24 years average  Source
3. 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
4. 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

## I Can’t Sleep: Caffeine Math Part 3 USA UNITS

November 13, 2021

## I Can’t Sleep Math: Caffeine Maths METRIC HERE.

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.

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.

## Holiday Music: The Random Playlist & Not so Random Math

June 18, 2021

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

## Real World Maths: Powers and the LOUDEST Rock Band in the world

October 22, 2020

#### Rock Concerts CauseTemporary Hearing Loss in Teens

Deep Purple: The Loudest Rock Band Ever

Lime Cordiale, a popular band in Australia

Find dB answers here.

## Isaac Newton, The Great Plague and how he filled in his Time!

March 18, 2020

I am grateful to Jeff Jacoby and his column, 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 Equation that tried to break the internet!!!

August 3, 2019

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

## VAMPIRES: a math horror story

March 6, 2019

You will find TWILIGHT TV series Math here.

## Math Nerd Love

February 14, 2019

The New York Times (The Perfect Valentine? A math formula 14 FEB 2019) has published an interactive widget from my favourite math website IMAGINARY for Valentine’s Day.

Here is the formula:

You’ll find IMAGINARY’S  interactive LOVE widget HERE.