How long does it take to jump from San francisco bridge?

How long does it take to jump from San francisco bridge? That is how long a person would be in free-fall?

Golden gate bridge elevation is 67 meters.

So using high school physics:

 distance = 1/2 g t^2

67 = 1/2 * 9.8 * t^2

This gives in my scheme interpreter for time of 3.7 seconds:

(expt (/ (* 67 2) 9.8) 1/2)

;Value: 3.697765458727081

Speed

What would his speed be at the time of his free-fall experience broken?

 speed = gt

(* 9.8 (expt (/ (* 67 2) 9.8) 1/2))

;Value: 36.2381014955254



That is 36.24 m/s!

or:

(* 3.6 (* 9.8 (expt (/ (* 67 2) 9.8) 1/2)))

;Value: 130.45716538389144

 130 KM per hour or close 81 M/hour - Nasty!

Force

What would be the force?

F = d(MV)/dt

So for a person of 70 KG, assuming the final splash down happens in 1 micro-sec in Newtons:

(/ (* 70 (* 3.6 (* 9.8 (expt (/ (* 67 2) 9.8) 1/2)))) .01)

;Value: 913200.15768724

This is equivalent to 91 TON on top of the person - or close to 45 elephants on Top crushing the bones! Not very nice way to go!

My reasons for evolution being true

My reasons for evolution being true or should I say for evolution being obvious, at least in hind sight?  In particular, why human beings are just another animal species although with some remarkable abilities, in particular in brain.

1.  Chimpanzee

When we see a Chimpanzee It looks remarkably similar to us. If we are special why do these guys look very similar to us? Just to fool us in to thinking that we are their cousins? In fact, to me these guys are the 'missing' link! Only an idiot can miss the link...

2. DNA

Why do we have the same DNA made up of same 4 bases [Adenine, Thymine, Cytosin, Guanine]? Why didn't we get created through some other genetic code. This makes it look very very obvious that we evolved from same animals [more exactly from our common ancestors].

3. Germs and diseases

We get pretty much the same diseases as other animals from very similar viruses and bacteria. For example, we get swine flu - So pigs and humans have to be quite a bit similar for these viruses to survive in both the species. In fact we are very similar - we are both mammals.

4.  Breast feeding

Both woman and other female animals breast [or udder] feed their young through nipples in very similar ways. It is striking in particular for other primates.

5. Kangaroo

Why are no Kangaroos to be found in say India, United States or Germany? If every species are specially created there is no particular reason to place all species of Kangaroos in Australia or near by.  Why not place red kangaroo in Australia and Grey one in say India?

Doesn't the geographical distribution of all animals make it very clear, all closely related animals evolved from their common ancestor which happened to be in one particular geographical location. 

Before the invention of air planes, one particular species had to be in close proximity for reproduction and survival. It is another matter, now we have become planetary wide pests like cockroaches or rats.

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Practical Innovations that changed the world!

1. Faraday's discovery of induced current from changing magnetic flux which runs our economy now. Think of a world without electricity - no light, no tv, no laptop and no internet!
2. Graham Bell's invention of Telephone - It totally changed the way we communicate. Precursor to this is Telegram and Cellphone is successor.
3. James Watt's Steam Engine and Trains - it changed the way people move.
4. Wright brothers' invention of air planes - of course, it also changed the way we move.
5. Computers - it changed the way people do work, buy, entertain. All kinds of reservations, shopping and great scientific endeavours like 'curiosity'.
6. Ability to make controlled fire. It changed the way we eat or build things.
7. Agriculture - It again changed the way we eat.
8. Ability to forge metals.
9. Counting in base 10.

 Did I miss something more important?

What is Temperature?

I was thinking about what is Temperature.


What it means for something to be in particular temperature? I looked around in the net, and learned that it is simply average kinetic energy of molecules.

If something is hot, the molecules in that something is moving around or oscillating faster. In the case of metals it is electrons. If something is cold, the molecules are relatively slow.

Why do we feel hot when we touch a hot object? The molecules in the object collide pretty hard on our fingers, trying to disturb our cells which is felt by our neurons as 'hot'.

Why do we feel cold? When molecules in the air is taking away average kinetic energy from us through collisions and we lose energy [heat].

What's the use of physics?

One word answer - Electricity.
Can you think of living in a world without electricity? What we take for granted came from physics.
Although that's not the reason for physics [its for its own sake] its the utility of it.
So today's Mars exploration etc. will turn into tomorrow's 'Electricity'.

Magical scientific facts

1. What we see is only part of the Electro magnetic spectrum.
2. Energy and mass is related through speed of light. What? what is speed have to do with mass or energy!
3. Time is not absolute. No simultaneity.
4. Gyroscope turning.
5. Brain seeing faces all over the place. Hollow mask.