@Akash.B Maybe I'm not seeing the whole picture because I'm not a regular in this room, but that question seems more like a speculative science question that like something would fit in a room about "problem-solving stragies."
@JohnRennie I did get the answer to that question as B , which is correct using this logic
since during the upward journey , the rotation of the cylinder eventually dies out , friction must be acting in the upward direction , to provide an anticlockwise torque (for the clockwise rotation) . Also, when the cylinder moves down the plane , the anticlockwise rotation of cylinder keeps increasing , so the friction would again act in the upward direction , to provide an anticlockwise torque , supporting the rotation this time.
Now as tortoise starts moving along a chord , it must be nearing the center of disc , so
@JohnRennie oh yea let me correct it
$L_f=(MR^2/2+mr^2)\omega_f$
$\omega_f$ increases here.
now the tortoise would continue moving and would be getting away from the centrer again. So , $\omega$ would once again decrease , as I would increase.
But it's obvious that $I$ decreases then increases again, so it's obvious that $\omega$ increases then decreases again. The only question is whether it's linear i.e. B or D
In physics, the center-of-momentum frame (also zero-momentum frame or COM frame) of a system is the unique (up to velocity but not origin) inertial frame in which the total momentum of the system vanishes. The center of momentum of a system is not a location (but a collection of relative momenta/velocities). Thus "center of momentum" means "center-of-momentum frame" and is a short form of this phrase.
A special case of the center-of-momentum frame is the center-of-mass frame: an inertial frame in which the center of mass (which is a physical point) remains at the origin. In all COM frames, the...
@Akash.B we describe the geometry of the universe by a function called the metric, which is a function of time. At time zero this function becomes infinite, and it's that moment that we call the Big Bang.
So the question is whether the metric can become infinite again.
Ah, OK, when you said you solved it using integration I thought you meant you had integrated the force over the slanted area, which is quite a calculation!
But anyway, we are in effect projecting the force on the slanted surface onto the area of the base.
So we're kind of doing the projection you talked about.
@AvnishKabaj Isn't that just treating the cylinder as two half cylinders i.e. you slice it along the middle then equate the pressures on the curved surface and the flat slice?
But those rhodopsin molecules are only sensitive to certain photon energies. IR light has too little energy to cause a transition and UV has too much energy to cause a transition. So both of those cannot be seen.
@Akash.B that is a phenomenon called optical dispersion. It happens because the refractive index of the prism is not constant but changes with wavelength.
@Akash.B the plane doesn't fly off into space because it isn't moving in a straight line. It's actually flying slightly downwards so it curves round the Earth instead of moving straight off into space.
@MadhuchhandaMandal as a general rule it's hard for a fast moving particle to be captured because it has too much energy to form a bound state. When the particle encounters the nucleus it's total energy will be whatever binding energy there is plus the original kinetic energy.
If that original KE is very large there is no chance of forming even a transiently bound state.
@JohnRennie Okay I see.. But I kinda tried to apply Le Chatelier's Principle : As Absorption of Neutron leads to radioactive decay , so the System becomes more stable due to release of Fission energy. So when the Energy of the Neutrons is increased more Absorption will take place (because Absorption leads to decrease of Energy of the system).
(a) Le Chatelier's principle is just a phenomenological rule that is unreliable and (b) it applies only to the sort statistical systems we get in thermodynamics and not so single nuclei.
Le Chatelier's principle? Really? Do they teach that to students these days?
I though science education had moved on from that sort of thing.
@MadhuchhandaMandal there is a lot wrong with the way that students are treated in India, and I'm sure everyone suffering through JEE preparation would agree. But I have to say that you emerge from the far side of the JEE process with some pretty amazing skills at doing physics problems.
It's obviously not true that $P=n$ but in many cases when we're doing calculations we'll find the constant $k$ can be cancelled on both sides of the equation so we can just omit it.
@GaurangTandon JEE is well known for asking conceptual questions and the closest concept we were taught in the regard to predicting direction of reactions is Le Charlie's . So I thought they are asking for that concept rather than being factual
The actual question is: In adiabatic expansion of air, (assume its mixture of $\ce{N2, O2}$) , the volume increases by $5\%$ , the $\%$ increase in pressure is?
@JohnRennie Uhm , what does the question mean by dispersion ? Dispersion as in diverging of light rays by concave lens , or dispersion of light by a prism to generate a spectrum
So when we shine our ray of light onto the glass plate the light refracts towards the normal, and the blue light refracts towards the normal more than the red light.
But ... when the light reaches the glass-air interface on the other side of the glass plate the light refracts away from the normal, and the blue light refracts away from the normal more than the red light does.