## 10. You can out run a lava flow … METRIC

November 17, 2018

This is a rework of a previous post with full calcs.

Every volcano disaster movie from Volcano (1997) with Tommy Lee Jones to Dante’s Peak (1997) withPierce Brosnan someone somewhere tries to out run a lava flow. Is this possible?

The answer is maybe. You will find everything you want to know about lava flows here.

On January 10,1977, at Nyiragongo lava sprang from the sides of the volcano moving at speeds up to 40 miles per hour (60 km/hr). About 70 people were killed.

Measuring the temperature of lava. Photograph by R.L. Christiansen, U.S. Geological Survey, January 9, 1973.
The fastest Lava flows recorded were in Hawaiiin 1950 when Mauna Loa erupted. The lava traveled at 10 kilometers per hour through thick forest. But once the lava flows became established and good channels developed, the lava in the channels was flowing at up to 97 kph.

Speed of average sprinter = 16 – 24 kph

October 23, 2018

# Star Stuntman

Star Stuntman Monte Perin (pictured) has involved many films, including “Spider-Man,” “Star Trek, “Indiana Jones and the Kingdom of the Crystal Skull” and portraying Arnold Schwarzenegger’s stunt double in “Terminator 3: Rise of the Machines.”

Perhaps his most difficult stunt was landing his Harley in an open boxcar of a moving train for Disney’s 2008 Adam Sandler movie “Bedtime Stories”. In a career of over 25 years Perin has broken “almost everything” including both his arms, legs, knees, feet, ankles, several ribs, his back and his pelvis. See Confessions of a stuntman

Veteran stuntman Evel Knievel (1938 – 2007) was the pioneer of many stunt jumps. Here he is jumping 10 cars and 3 vans in 1973.

His injuries are legendary:

More Evel Knievel

# Ramp Design

The angle of the kicker in ramp design can vary from 100 – 700 (See below)

# Moto-X Ramp Jump Maths

The Problem?

If the ramp angle is too high, the stunt jumper also goes high, but doesn’t travel very far.

If the ramp angle is too low, the stunt jumper doesn’t stay in the air for very long and therefore doesn’t travel far. (see below0

The stunt jumper wants the OPTIMUM RAMP ANGLE.

## METHOD 1: TRIGONOMETRY (cos we can)

As any bike nut knows increasing speed at ake off will increase jump distance.

Here is a graph from final gear for speed vs angle to jump 90m.

# METHOD 2: MORE TRIGONOMETRY

METHOD 1 is approximate (See STEP 1 & STEP 2 above), but as METHOD 2 produces the same ans (See above), it is very useful.

You will find a thoroughly detailed calc for STUNT JUMP MATHS here:

And everything you ever wanted to know about PHYSICS OF STUNT JUMPS here.

October 2, 2018

# Take 2:

Structural Engineer Ron Klemencic explained on the Discover News that a simple rule of thumb for calculating skyscraper sway was to simply divide the buildings height in by 500 because the building codes demand the building fit a 1:500 sway ratio.

The tallest building in the world at 2,716 feet (828m), the Burj Khalifa, Dubai, would sway back and forth about 5.5 feet or 1.7 m.

Ahhhhhhhhh!  But you would have to drag Mathspig onto the 168th floor screaming.

But mathspigs you can work out the sway on the top ten tall buildings in the world.

## Death by Caffeine: The Maths  Part 1 METRIC

September 10, 2018

Death by Caffeine: The Math  Part 1 USA UNITS here.

The lethal dose for caffeine is about 150 milligrams per kg of body weight. While the average person’s caffeine consumption is around 200 milligrams a day, the Mayo Clinic advises against exceeding 500 to 600 milligrams per day.

This work titled Timing is Everything is by street artist ABOVE in London.

You may want this much energy but be warned, energy drinks can kill.

It would take a ridiculously huge number of ANGRY WOMBAT energy drinks to kill a 14 year old weighing, say, 48 kg. Nevertheless, some kids are more sensitive to caffeine than others and then much lower levels of consumption of energy drinks can be fatal.

See Death by Caffeine: The Maths Part 2 METRIC

Here is the work (see below) TIMING IS EVERYTHING by street artist ABOVE in London showing the timing.

May 8, 2018

# The amazing maths of volcano eruptions.

Once lava flows are established new RIVERLETS can run on top of the original lava flow at great speed.

The fastest Lava flows recorded were in Hawaii in 1950 when Mauna Loa erupted. The lava traveled at 6 miles (10 kilometers) per hour through thick forest. But once the lava flows became established and good channels developed, the lava in the channels was flowing at up to 60 miles/hour (97 kph)

# Can you out run a lava flow?

You are 2 km from the volcano rim and start running.

VL =   97 kph = 1.6 km per minute (k/min)

=   60 mph

VH = 18 kph = 0.3 km/min

= 11.2 mph (miles per hr )

May 7, 2018

# The amazing maths of volcano eruptions.

One of the greatest dangers in a volcano eruption is not the lava flow OR being hit by a lump of flying lava or rock, but by being choked by the fast moving scorching hot pyroclastic cloud.

In 1991 pyroclastic cloud blew out of the side of Mount Unzen in Japan. NASA has an excellent diagrams for such an event here.

According to the NASA website:

Highly mobile, these flows reach velocities of up to 400 kilometers (250 miles) per hour and can spread as far as 100 kilometers (60 miles) from the eruption point.

# Can you out run a pyroclastic cloud?

Here is what happened in 1991 when the pyroclastic cloud blew out of the side of Mount Unzen in Japan.

August 14, 2017

# The Solution:

## You are going to use this maths NOW……………..

……………………………………………………………………..

# How much alcohol will kill you?

## TOPICS: Decimals, %, algebra, vol, weight units (Metric)

At low levels of consumption alcohol impairs decision making and inhibits coordination. It makes you DUMB and CLUMSY, which can cause serious injuries if you, say, fall down stairs.

Legal Age to Buy or Sell Alcohol USA: 21 years

Legal Age to Buy or sell Alcohol AUST, NZ & UK: 18 Years

Legal Age to Buy or sell Alcohol CANADA: 18 – 19 Years depending on region.

At higher levels of consumption ALCOHOL can kill. It is a depressant. It acts on your central nervous system. It can STOP YOU BREATHING.

WORKED EXAMPLE

1. Calculate the weight of (pure) alcohol or ethanol in the following standard drinks using the following information:

Now Ethanol =  0.79 gm/ml