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Heat & Cold

My brother was arguing that heat & cold could be separate entities and I’ve told him what is known is that cold is the absence of heat and they are just a representation of one thing similarly to how darkness is an absence of light. Having told him that, he asks why are they not considered similar to salt & water? This lead to an interesting thought experiment. At 1st I highlighted the obvious to him of the tangible chemical formation of salt & water making them separate and detectable so, whereas you can’t do the same with heat and cold they aren’t detectable both there. This is when he says that maybe they are. And having recently read about the lucid fallacy, I decide to hear him out, casting aside common examples that show they are a mere representation of low and high temperature.  He basically said if they aren’t separate entities wouldn’t a vacuum have no temperature rather than be cold?


Travelling back in time by increasing speed?

Is it true statement that travelling faster than speed of light and travelling back in time both are same thing.how ?

Asked  Chandan Kumar

Time Period of a Simple Pendulum

The time period of a simple pendulum of length L fixed on the top of a rocket moving upwards with a constant acceleration g is .. ?

Asked Amandeep

Projectile Motion

A projectile is projected at an angle theta with horizontal with speed u . If air resistance is taken in account , the angle with vertical at the time of hitting the ground will be a)more than (90 + theta) b)less than (90 – theta) c)(90 + theta..

 Iman Bint e Abbasi

moving through parallel universes

could it be theoretically possible for a person to die in a certain universe and wake up in a similar universe like a shift leaving that person being the only person aware of this change, also could everyone be one and the same person like one consciousness experiencing itself in many different ways at the same time

Asked Paul Appleby

black holes

A photon does not experience time since it moves at the speed of light. time stops for it . however we can continue to measure the time for which the photon moves from one point to another and are able to observe it move from one point to another.
so how is it at the event horizon when something is being pulled at the speed of light into a black hole we cannot see it being pulled into the event horizon and passing the event horizon. the explanation that is given is that no amount of time can pass that will be enough for us to observe this. but just like the photon time has stopped for the one being pulled not the observer so shouldn’t we be able to observe the object move into the black hole ?

Asked Muntasir Hossain


The hook to hang  a ceiling fan is not in the ideal point. I wish to hang the fan appox 3feet away from the hook and below 2feet by mean of a iron rod bent/fabricated/designed accordingly joining/hanging it to/from the available hook as i mentioned. please mention some designs for iron rod that would keep the balance right for the purpose.

Asked Soumya

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