Archive for the ‘Simultaneous Equations’ Category

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5. You can jump out of an airplane that is about to crash and catch the baddie who took the last parachute.

January 10, 2019

 The names Bond, James Bond. In Moonraker  with Roger Moore (1979) 007 jumps out of a plane without a parachute to avoid an assassination attempt. He catches up with, Jaws, arch-baddie, in mid-air and takes his parachute. Jaws survives his fall by landing on a big top circus tent.

In Point Break with FBI agent Johnny Utah, Keanu Reeves, leaps from a skydiving plane after Patrick Swayzes’ characer, Bohdi, who has taken the last parachute. Utah catches Bohdi in mid-air, and after a tense confrontation with a gun, both survive using Bodhi’s chute. The remake was in 2015.

There are more movie and real life stories at the  Free Fall Maths link.

Note: We’ll assume Bhodi and Utah have equal horizontal velocities (plane exit velocity plus wind) so the following calculations only involve the vertical or falling velocity. The terminal velocities used for Bhodi and Utah are realistic estimates. 

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10. You can out run a lava flow … USA UNITS

November 17, 2018

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

Dantes_peak_ver2Every volcano disaster movie from Volcano (1997) with Tommy Lee Jones to Dante’s Peak (1997) with Pierce 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.Volcano_ver2

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

 

lava temp 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 6 miles 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 mph.

Speed of average sprinter = 10 – 15 mph

Can you out run a lava flow?

 You would be scorched in 33 seconds!!!

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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) withDantes_peak_ver2Pierce 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.Volcano_ver2

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.

lava temp 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

 

Can you out run a lava flow?

You would be scorched after 3 minutes!!!! 

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Maths News: Volcano Survivor 2

May 8, 2018

Kilauea erupts in Hawaii MAY 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.
Puu-Oo-USGS lava riverlets

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 )

GRAPH:

How long will it take for the lava to catch you?

Mauna Loa Volcano Lava Flow 1950 2

 

SIMULTANEOUS EQNS:

How long will it take for the lava to catch you?

Mathspig simultaneous Eqn 2

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Maths News: Volcano Survivor 3

May 7, 2018

Kilauea erupts in Hawaii MAY 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.

Mt Unzen volcano-world

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?

Mathspig simultaneous eqn 3

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

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The Terrifying Maths of Running from a Bear … Metric Units

July 17, 2017

METRIC UNITS below. USA UNITS here.

BEAR STATISTICS

Grizzly Bear

Weight:   250kg

Height:   250cm

Top Speed: 56kph  =   16 m/sec

More bear stats here. 

Brown Bear

Weight:  680kg

Height:   250cm

Top Speed: 35kph  = 10m/s

More bear stats here.

Comparing these speeds to the fastest man on earth, Usain Bolt:

Usain Bolt:

Top speed: 243kph =   12m/s

So Usain Bolt could out run a Brown Bear but NOT a Grizzly!

Bears are NOT as dangerous as:

In fact more Americans die choking on their own vomit each year than a re killed by bears.

More death stats here.

But bears are very fast so Park Rangers recommend the following survival tactics:

More bear survival info here.

REF: Dog helps save hikers after grizzly chases them for 20 minutes here.

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The Terrifying Math of Running from a Bear … USA Units

July 17, 2017

USA UNITS below. METRIC UNITS here.

BEAR STATISTICS

Grizzly Bear

Weight:  550 lb        

Height:  8’ 2”   

Top Speed: 35 mph  =   51 ft/s    

Brown Bear

Weight:  1,500 lb       

Height:  8’ 2”              

Top Speed: 22 mph  =  32 ft/s     

Comparing these speeds to the fastest man on earth, Usain Bolt:

Usain Bolt:

Top speed: 27 mph  =   40 ft/s     

Bears are not dangerous:

………………………………………………………………………


In fact, more Americans die each year from choking on their own vomit than are killed by bears.

More death stats here

Nevertheless, bears are very fast. So you can see why Park Rangers offer the following advice:

More information at Mountain Nature.

The reason for waiting until the bear is 15 ft away is to make sure the spray doesn’t disperse in the air. If the Pepper Spray is too spread out it will not stop the bear.

Ref: Dog helps save hikers after grizzly chases them for 20 minutes.