Archive for the ‘TOPICS’ Category

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7. You can safely jump from a burning skyscraper/bridge/aircraft into water.

December 13, 2018

Angels and Demons (2009) Tom Hanks character, Robert Langdon, hero of Dan Brown’s jumps from a helicopter and falls thousands of feet into Rome’s Tiber River and survives, of course.

Ahhhh! Look up. It’s raining Tom Hanks!!!!!The Hulk (2003) The Hulk hops from the Golden Gate bridge onto a jet fighter, whose pilot tries to get rid of him at high altitude. The Hulk falls off and plummets many thousands of feet into the bay. He survives.

There are 2 factors we must consider when jumping or diving from a great height:

1. Surface Impact

2.Water depth 

1. Surface Impact

According to the Free Fall website falling into water is not a good survival strategy. 

‘Someone falling without a parachute from more than 2,000 feet or so would be falling quite a bit faster than 100 miles per hour (161 kph) The folks who have survived falls into water have had streaming parachutes above them, which probably slowed their falls to the 60 mph range (97 kph). Having a streaming parachute helps in another way because it aligns the body in a position where the feet enter the water first.’

The website goes on to explain that water is an INCOMPRESSIBLE FLUID. It’s like landing on concrete. Landing in mud, on snow, on trees, on circus tents etc helps break the fall. Moreover, jumping off a bridge into turbulent sea may be safer than jumping into calm water.

On 24th Oct 1930, Vincent Kelly, 31, while working on the Sydney Harbour Bridge fell 170 ft (52 m) into Sydney Harbour and survived.

A champion diver he did several summersaults and landed feet first. He broke a couple of ribs as he did not enter the water at a perfect RIGHT ANGLE but rather a few degrees off perpendicular..

2. Water Depth

The next issue is, if you are going to dive or jump into water from a great height and, miraculously, survive the impact, how deep should the water  be?

Olympic divers often practice their dives in a bubble pools (like a spa). This reduces the impact for a bad dive but the water must be much deeper. Sports Smart Canada recommends a water depth of double the height of the drop. But is this realistic if, say, you are jumping or diving from the top of a waterfall into aerated water.

You can work out approximate depths needed if you were jumping into calm water from heights such as below:

How deep do you plunge? The answer is surprising because, in fact, you decelerate really fast in water.

See REd Bull Jump Science here

Thanks to Rod Vance  for the Fluid Engineering Calcs (done by hand … not by computer program) for calculating the depth of water when your feet stop moving. That is the minimum depth of water needed for the jump (See graph below)

NOTE: Even with this fancy maths assumptions must be made about the transition epoch-half in/half out of the water.

 Assuming you survive the impact and you breath out through your nose – to stop water going up your nostrils really fast- then you will not go any deeper than approx 4 m or 13 ft from a platform of 20 m (65 ft) or less.

If you’re diving into water from, say, a helicopter as in the Demons & Angels movie you don’t need extremely deep water. Assume Langdon was at 100m (328 ft) or the height of The Statue of Liberty(above) or a 33 story building  when he jumped, then extrapolating the graph (above), maybe, a depth of 5m (16 ft) would do.

If you want to see what looking down from a 58.8 m (193 ft) platform looks like check out thisWorld Record Jump by Laso Schaller.

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8. You can survive any amount of beating in a fight.

December 6, 2018

Lethal_Weapon_4_PosterDie_Hard_With_A_Vengance

 

 

 

 

Every action hero gets into a fistfight. James Bond, Jason Bourne, Indiana Jones. Then there are all the stars known for their fight scenes. Sylvester Stallone ( Rocky),  Arnold Schwarzenegger (True Lies), Jackie Chan (Any movie), Bruce Willis (Die Hard 1,2, 3 etc), Mel Gibson (Lethal Weapon I, II, III etc), Jean Claude Van Damm (Blood Sport, Street Fighter), Brad Pitt (Fight Club), Fast & Furious 1,2,3 and so on.

But can the human body take this punishment?

We can work it out. Measurements taken at The University of Manchester have shown that local boxing hero Ricky ‘The Hitman’ Hatton really does live up to his name. (DailyScience)

ricky 'the hitman" hatton

Ricky ‘The Hitman’ Hatton can pack a punch!!!!! 

Similar results were found at Uni Manchester BBC (Force of boxer’s punch measured)

So one punch is equal to being hit by a car …… if only for a split second!!!!!!!!!!! Nevertheless you can be killed by this one punch.

You’ll find some great punching physics here

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9. A single match or candle will light a room the size of a football stadium.

November 21, 2018

 

This is the rework of a previous post.

Action heroes such as Indiana Jones or even film kids like Tom Sawyer or The Goonies who go into a cave, anabandoned house, a crypt or a catacomb light the entire place with one match, one candle, a lighter or a cellphoneIndiana jones 1tm sawyer.

Is this real?

 

Now mathspigs, if you are interested in a career in stage/film lighting or even architecture you will need this maths.light globe_tns

 

60Watt light globe tells us how much power it uses. But some 60W globes are brighter than others. Light is measured with weird units.

candle_tnsUSA uses Foot-candles. Can you imagine the pickup line ‘You brighten up my world like a footcandle’? A foot-candle is the brightness of a candle 1 foot away. Now think of a bubble around the candle. Brightness is mostly measured using one square foot or one square metre of that bubble:

1 LUMEN = 1 Footcandle/ft squared

1 LUX = 1 footcandle/m squared

Don’t get too hassled by these units.  As a rough rule:

1 candle = 1 LUX

candle 1 Correction

candle 2 Correction

candle 3 Correction

From graph you can see by 3m a Birthday Cake is not very bright even in a haunted house or crypt.

Challenge: Draw a graph of the brightness of your own Birthday Cake!

Big Challenge:Draw a graph of your Teacher’s Birthday Cake!!!!!! Ahhhh!!!!

We know:

1 candle = 1 LUX

Now compare the brightness of 1 candle to the brightness of other sources of light:

If you want sufficient light to live your everyday life you’d need:

80 candles just to go to the toilet!!!!!!

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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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What do the Sydney Opera House and Freddie Mercury have in common?

November 6, 2018

Freddie Mercury is back in the news with the release of the new biopic BOHEMIAN RHAPSOSDY. ( Mathspig gives it ⭐⭐⭐⭐⭐. But I’m a Freddie fan. ) So Freddie and the Opera House? What do they have in common?

NOTE: Uncanny likeness of biopic actors to the real Queen!

According to intmath The Sydney Opera House is a very unusual design based on slices out of a ball. Many differential equations (one type of integration) were solved in the design of this building.

You will never see a better parody of Queen’s ICONIC song BOHEMIAN RHAPSODY than Calculus Rhapsody By Phil Kirk & Mike Gospel (below).

And if you need to be reminded of the maths you will find links to texts here.

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1. Movie Stunt Math: Rolling a CAR

October 29, 2018

“With enough stupidity you can get any car to roll over” (MSN AUTO)

What stuntmen and women need is maths!

Maths is essential to the process, from calculating speeds and braking distances to looking at the ratio of the amount of film shot to the length of time of the end sequence. The stunt and crash is outlined, and the co-ordinator explains how he must calculate speeds and stopping distances carefully.

So you want to be a stuntman?

First think of the pain.

Mark Eiden, 52, a professional stuntman (pictured) who is not only afraid of heights, but was once told he likely wouldn’t walk again. Eiden’s had surgery on both arms and shoulders, five knee surgeries, six nasal reconstructions, foot and hand surgery and a facial cast. He fell off the top of a stunt car at 40 mph when the tyre blew. He gaffer taped his ear and continued, despite severe concussion. Northern Express Michigan

1 J Mark Eiden Northern Express

If you still want to be a stuntman do the Maths:

Rolling a Car:

You can use quick handbrake turn, speed around a corner, fishtail into the curb or some other lunatic thing. The most controlled way to roll a car is to use a ramp.

ramp caranddriver.com

These ramps often have a kicker at the end to add extra lift. Ramp calculations can be complicated, but the simplest way to look at the maths is to determine the angle a car will roll ie. When the Centre of Gravity moves over the base.

Centre of Gravity vs Base Width

The distance between the front wheels in cars is often called the track width.

1a Centre of Gravity

2 Stable Couch3 SUV angleBase vs CofG SUVsTable from Accident Reconstruction Website

4 Bus Centre of Gravity

5 Small car centre of gravity

6 Lambogini Diablo Centre of Grvity

So the Lamobgini Diablo is very hard to roll (build a higher ramp) and it therefore beats the SUV for stability every time.

Balancing on 2 Wheels

A more skilled stunt involves driving a car on two wheels. A very skilled stunt driver can lift the car onto wheels by snaking the car back and forth across the road until it balances on 2 wheels.

From the Centre of Gravity vs Base angles above you can see that the SUV is the easiest car to balance of 2 wheels.

But there is nothing quite as crazy as this SUV stunt:

Saudis changing car tyres, just insane.

Picture 1

View full video here.

Safe Driving Info here