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Why is it dangerous to stand in the upper deck of a double decker bus?

A modern Ashok Leyland BEST double decker bus

Why is it dangerous to stand in the upper deck of a double decker bus?

Asked Sona

Raja Bhargab Answers:
“a body is said to be more stable when its CENTER OF GRAVITY is kept as low as possible. In a double decker bus , the c.g. of our body is obviously at higher place than the lower deck.In addition , if we stand the c.g. goes the higher , which will lead for a great imballance to be followed by a severe fall off. Moreover,when the bus moves or jerks,in lower deck,the moment of deflecting force is tolerable . But in the upper deck,it’s tremendously high”
A double-decker bus plying in the 122 route fr...

Resistance and Resistivity

Simran Asked

“Two wires A and B of equal lengths,different cross-sectional areas and made of same metal a)name the property which is same for both the wires. b)name the property which is different for both the wires”

Answer:

Since both the wires are of same metal, the resistivity will be same for both whereas since the dimensions (Area of cross section here) are different, the resistance will be different

Gravity and something more

Jihin Asked:

Some Things That I Have Always Wondered OF : (i hope it may be answered soon …)
1)is it possible that our human body can withstand pressures twice or more than the atmospheric pressure without a suite or is there any artificial instruments or means in which our heart can be made to pump into a level in which we can attain this ability !!!
2)when more gravity  is experienced , it is said that time travels slowly – is it  relative ??? caz time goes at a constant rate !!! it is only the position or view that makes the observer feel the situations ???
3) Is there any gravity chambers successfully made out … in which the gravity can be changed accordingly to observe diff. phenomena ??? Cant It be possible to do that ????

Ans:

To be posted soon.

However, I agree that I may not be able to give you a satisfying answer to all your queries, as “Science says the first word of everything and the last word of nothing.” We are learning new things everyday. When we explore more and more, we find that we know less and less and our knowledge is too meagre.

By the time I prepare a well fitting answer to this, visitors are also requested to respond to the question by posting answers and comments.

Physics.org Award winning websites

http://scienceblogs.com/startswithabang/

http://www.zooniverse.org/

http://www.popsci.com/

http://www.cosmosmagazine.com/

http://www.guardian.co.uk/science/series/science

http://www.physicsforums.com/

http://www.last-word.com/index.php

http://www.nasa.gov/audience/forkids/kidsclub/flash/index.html

https://project-cernland.web.cern.ch/project-CERNland/index.html

http://www.physics.org/

http://www.sciencefairstl.org/

Form of Kepler’s in a different universe!

Mukta asked:

“imagine a planetary system in which gravitational force varied as 1/r instead of 1/r2 .what relation would correspond to KEPLER’S THIRD LAW (SQUARE OF TIME PERIOD / CUBE OF SEMI MAJOR AXIS.?”

(Answer)

If the gravitational force varied as 1/r instead of 1/r2 , then Kepler’s Law of periods would have to be modified accordingly and it would give T proportional to r.

Time Travel Again !

Davide Writes: (The email is posted as such. SO, sorry for the telegraphic language and poor spelling and grammar)

“Hello there i have one more question,a crazy one:) according to Einstein we need a enormous amount of energy to push matter at a speed of light,now for me the real problem there  is that an atoms at a speed of light will break a part right?so even if we will find a way to push it,we will still failed.I was wander are we looking to the right way?is it photon, so the world of small with no mass only work? now here my crazy question,lets speculate a bit,we have two red dwarf pretty close to earth Barnard’s Star” only  “5.9 ly and Wolf 359 7.7ly a baby step compere the universe,if we can send a same kind of mission the we have done with Stardust Nasa’s comet sample and collect a piece the size of a soccer ball back to earth,we could work on it outside earth atmosphere in the space base.Since we can’t go in the first place at a speed of light let’s says that the all deal will last 150 year to go and back,(assuming that we use a new energy to go bit faster)in the mean time the space base will be pretty developed and maybe we even found a new power to push to the speed of light(i remind you that we are speculate)we could put our hands on the sample using electromagnetism so that we avoid any risks and then send it at a seed of light.What i try to say is that a single atom is weak but billions of it together is a different story,here an example, lets imagine to make a spherical shape out of Lego(the toy) and send it in to space at a great speed,it will break pretty soon,now we make another one but we glue the piece together,it will last bit longer,again another with glue and a put net around it will last even longer so instead of a Lego we use our sample,the glue in the inside is the immense mass that will have (piece of red dwarf) net outside the  immense gravitational pull ,now do you think that it will be enough to keep it together at a speed of light?regardless the energy that we need to push it?  after all even in the past we believed that going faster than a  speed of sound a plane will brake a part or something bad could happen,instead only a big BUM wen we reach it and nothing more,so maybe if we can go faster than light nothing will happen,or maybe we find a new way to travel,we can even give a name for fun “a speed of matter” what do you think about it?i know it sound like sci fi but hey physics it self is blowing mind science right?   Thank you kindly for your time:)”

I don’t like to respond now.

Responses from visitors invited

A body travels 100m in first 2 seconds and 104 in the next 4 second.how far will it gimove in the next four second if the acceleration is uniform?

A body travels 100m in first 2 seconds and 104 in the next 4 second.how far will it move in the next four seconds if the acceleration is uniform?

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