Archive for the ‘units speed’ Category
Toilet Paper FUN FACTS Maths
June 1, 2021
Mathspig is in Melbourne, Australia. We’re in Lockdown. AGAIN!
And toilet paper has disappeared off the supermarket shelves. AGAIN.
So today we are doing maths based entirely on toilet paper using information from the Toilet Paper Fun Facts website. Yes! It exists here.
Toilet Paper Fun Facts Website
Protractor Wind Speed Calculator
POP UP ANS Q 1 & 2 Yr 7&8 Toilet Paper fun facts
Pythagoras Equation Diagram here
Here is the Sine Rule (Watch 1.5 mins)
Check sine curve here:
Listen to sine curve here:
Ohtani vs The World ………………………. Some amazing fastball facts.
April 12, 2021
More Info: New York Times, 5 April 2021
Also: Which sport is more DANGEROUS to play? Cricket or baseball?
Tennis Math: Is player height a BIG advantage? USA units
February 13, 2021Metric version here.
The Australian Open is on at the moment in Melbourne in LOCKDOWN. (We have 1 community-acquired case. Tennis players are in a bubble.)
Is height a BIG advantage in tennis?
Here are the heights of 3 top seeds in the Australian Open. (See graph below)
No. 1 Novak Djokovic 6ft 1″ (73 in)
No. 6 Alexander Zverev 6ft 6’ (78 in)
No. 8 Diego Schwartzman 5ft 7’ (67 in)
1. Does serve speed increase with height?
That would be an advantage. Here is a Height vs Serve Speed chart for the Top 6 seeds in the tournament:
Find serve speed data here.
There is NO CLEAR HEIGHT ADVANTAGE for serve speed.
2. Does the serve return rate increase with height?
Here is Diego Schwartzman (L) when he defeated Alexander Zverev (R ) in the 2019 US Open.
What is Schwartzman’s Super Power?
Schwartzman, the shortest player on the circuit (see graph above), tops the service returns stats. Highest 2nd serve return rate. Third highest 1st serve return rate. See data below. So agility, speed, and reaction times are also important factors in becoming a tennis star.
Go Schwartzee! Check data here.
Tennis Maths: Is player height a BIG advantage? Metric
February 13, 2021USA units post here.
The Australian Open is on at the moment in Melbourne in LOCKDOWN. (We have 1 community-acquired case. Tennis players are in a bubble.)
Is height a BIG advantage in tennis?
Here are the heights of 3 top seeds in the Australian Open. (See graph below)
No. 1 Novak Djokovic 188cm
No. 6 Alexander Zverev 198cm
No. 8 Diego Schwartzman 170cm
1. Does serve speed increase with height?
That would be an advantage. Here is a Height vs Serve Speed chart for the Top 6 seeds in the tournament:
Find serve speed data here.
There is NO CLEAR HEIGHT ADVANTAGE for serve speed.
2. Does the serve return rate increase with height?
Here is Diego Schwartzman (L) when he defeated Alexander Zverev (R ) in the 2019 US Open.
What is Schwartzman’s Super Power?
Schwartzman, the shortest player on the circuit (see graph above), tops the service returns stats. Highest 2nd serve return rate. Third highest 1st serve return rate. See data below. So agility, speed, and reaction times are also important factors in becoming a tennis star.
Go Schwartzee! Check data here.
Terrifying Tennis Maths: The Speed of Novak Djokovic’s serve. METRIC
February 7, 2021USA units post here.
Novak Djokovic is the No. 1 Seed in the Australian Open 2021.
His fastest serve = 219 kph
Could you return his serve? Do the maths!!!!!!
The ball leaves Djokovic’s racket and hits the ground 0.31 secs later.
Go here to see why this simplified calculation works!
Mathspig tested her reaction time here. TRY IT!
Mathspig’s best, best, best reaction time = O.33 sec
The fastest serve EVER was delivered by Australian Sam Groth @ 263 kph.
That serve takes 0.25 sec to land on the other side of the court.
Terrifying Tennis Math: The Speed of Novak Djokovic’s serve. USA units
February 7, 2021METRIC post here.
Novak Djokovic is the No. 1 Seed in the Australian Open 2021.
His fastest serve = 136 mph
Could you return his serve? Do the math!!!!!!
The ball leaves Djokovic’s racket and hits the ground 0.30 secs later.
Go here to see why this simplified calculation works!
Mathspig tested her reaction time here. TRY IT!
Mathspig’s best, best, best reaction time = O.33 sec
The fastest serve EVER was delivered by Australian Sam Groth @163.4 mph. That serve takes 0.25 sec to land on the other side of the court.
Real World Maths: RATES, pop song drumbeats and jogging
September 17, 2020
Australian Open 2020: Could YOU ….. return Roger Federer’s serve?
January 27, 2020The Australian Tennis Open is being played at the moment and Mathspig is always amazed at the serve speed of the top-seeded players.
Here are some of the serves speeds of players in this year’s Men’s Open.
Keep in mind the fastest female tennis serve by Barbora Záhlavová-Strýcová is a very respectable 225 km/h (140 mph).
Can you return Roger Federer’s serve?
NOTE: Andy Murray had the same serve speed as Roger Federer.
Go here to see why this simplified calculation works!
Mathspig tested her reaction time here. TRY IT!
Mathspig’s best, best, best reaction time = O.33 sec
Could Mathspig return Roger Federer’s serve?
Nooooo!…………………………………………………………………….
I’d be hit in the head by a speeding tennis ball
before I even moved.
But I’m a pig. I’ve got the best service GRUNT! Ha!
Amazing and Terrifying Wildfire Maths . . . . . . . . . . . . . . METRIC UNITS
November 13, 2019
With the catastrophic Californian fires burning into November and wildfires currently burning in NSW and Qld, Australia, I had to repost this firefighter maths for middle school classrooms.
Radiant Heat Stats WA Fire Dept FACEBOOK, Australian Bushfires 14 NOV 2019 MyFireWatch WA
Wildfires USA 2019 Map: Ecowest,
METRIC UNITS
Background Story
On 5th August 1949 Wag Dodge was dropped by parachute with 14 other fire fighters into Mann Gulch, a steep-sided gully in a Montana pine forest. Fire fighters who parachute in to put out small blazes started by lightening are called Smoke Jumpers. As they worked their way down the sides of the gully the breeze was blowing away from them. But the wind soon shifted. This produced an updraft, which increases the speed of the fire front. The 15 Smoke Jumpers turned and started running for their lives uphill.
HOW FAST CAN YOU RUN?
METRIC UNITS
Time Trial:
Mark out a 10 m course. Make 3 time trials.
t1 =
t2 =
t3=
Average your time:
tav = (t1 + t2 + t3)/ 3 =
Your Speed S = 10/tav = ……… m/sec
HOW FAST IS A GRASS FIRE?
This will, of course, vary depending on the wind speed. A typical grass fire in Australia in a flat area can travel at 20kph (up to 30 kph) in a gentle breeze.
Fire Front Speed Grass Fire
Fire Front Speed = 20 kph = 20 x1000/(60 x 60)
= 20 x 0.27777777 = 20 x 0.28 m/sec
= 5.6 m/sec
CAN YOU OUT RUN A FIRE?
Average Running Speed Boy 13–14 yo = 3.0 m/sec
Average Running Speed Girl 13–14 yo = 2.4 m/sec
We’ll assume, boy or girl, that you are really motivated and can run away from the fire at top speed of 3.0 m/sec. Now calculate the distance you can run and the fire front moves in 10 secs intervals up to 1 minute.
This is not looking good. See more Firefighters Need Maths here.
We can do very accurate calculations using simultaneous equations. Wildfire Algebra: Detailed Worksheet using simultaneous equations and solutions here.
NOW YOU ARE RUNNING UP HILL. WHAT HAPPENS?
We’ll assume, due to being motivated by having a fire licking your heels, that you can run at your top speed up hill for a short time, at least. But here is the problem.
Heat rises and so there is a Chimney Effect pushing the fire uphill. The rule of thumb used by fire fighters is:
Each 10º increase in slope, the fire front speed doubles.
Now you can calculate the distance travelled by the fire front up a slope at a 30º angle.
Don’t forget you can use the WEB 2.0 Calculator here.
Even at your top running speed, which is unlikely up a slope, you can run 180 m in 1 minute. In that time the forefront has moved 2688 m or 2.7 km.
It depends how far away you are from the fire front, but it seems you cannot out run this fire front.
Again we can do very accurate calculations using simultaneous equations.
See Firefighters Need Maths here.
Wildfire Algebra: Worksheet and solutions here.
CAN YOU OUT RUN A WILD FIRE?
High winds can turn a bush or forrest fire into a WILD FIRE with wind speeds up to 110 kph and temperatures up to 2000 °C, which can and does melt glass and cars.
The fire front speed doubles with every 10º, so speeds for the fire front can reach 220 kph, 330kph and up to 550kph.
What happened to the Smoke Jumpers?
When the fire front changed direction Wag Dodge and 14 other Smoke Jumpers found themselves running for their lives up a steep slope. What did Wag do next?
ANS: Here’s the amazing thing. Wag realised he could not out run the fire at that point. So he stopped. Took off his back pack. Took out some MATCHES and lit a fire in the grassy patch in front of him. Just before the firewall hit he threw himself face down on the burnt patch. He survived. The other 14 firefighters did not.
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