1. two boats moving parallel to each other and nearby are pulled towards each other. name the scientific theorem involved in the above cases. state and prove the theorem.
2. what are beats?name the basic phenomenon due to which beats are produced.two sources of sound are producing waves of frequency v1 and v2 where ( v1-v2) is small. show mathematically that the beat frequency is (v1-v2).
3. a body is projected with a velocity ‘u’ at angle theta with the horizontal. derive the mathematical equation of the path followed by the body and hence find the expression for the horizontal range. how will the horizontal range change if the angle of projection is changed to (90- theta).
4. using expression for pressure exerted by a gas on the walls of container, deduce Avogadro’s law.
5. a monkey of mass 40kg climbs on a rope which can with stand a maximum tension of 600N. in which of the following cases will the rope break:
a) if the monkey climbs up with an acceleration of 6m/s2
b) if the monkey climbs down with an acceleration of 4m/s2
c) if the monkey climbs up with a uniform speed of 5m/s
( ignore mass of rope. take g= 10 m/s2)
6. what is the need of banking of tracks?
7. the absolute temperature of a gas is increased to four times. what will be the change in its root mean square speed?
8. find the expression for apparent frequency observed by a stationary observer when a sound emitting source is approaching towards the observer.
9. a body weighs 63N on the surface of earth. what is the gravitational force on it due to the earth at a height equal to half the radius of the earth.
10. show that the co- efficient of superficial expansion of a rectangular sheet of the solid is twice its co-efficient of linear expansion.
(Posted by Ritika)
(Post your answers now!
I’ve been wondering about the following issue for the past few days, let’s assume all terrain on earth is plain, we have infinite supply of straight pipe sections we can assemble into a very straight long pipe all over the equator, if we observe a small part of the pipe let’s say, 10 or 100 meters it would appear straight, but as a whole, would it continue to be so straight that it would form an increasing angle with the surface as the planet’s surface becomes curved? Or would the pipe become ring along the planet? and in this case, how could it become a ring if it’s all straight pieces of rigid metal pipe? because of the curvature of space due to gravity? or because long things tend to bend in proportion to how narrow or thick they are respect to the lenght?? English is not my mothertongue, I hope i made myself clear enought in depicting the esense of my question. Thank you.
Posted by Jesus Bitar
What is the working principle of Van de Graff generator?
Akash Rai asked.
Answer: This is a question asked by many of the students.
There are basically two principles involved. The principle stresses in NCERT text book is that,
If we consider two concentric spheres connected electrically, then any charge given to the inner conductor will immediately be transferred to the outer sphere, irrespective of the amount of charge already present on the outer sphere. This happens because, the inner sphere is always at a higher potential and charges flow from high potential to low potential.
Another principle involved is the action of sharp points and corona discharge.
When a conductor with sharp points are charged, there will be greater surface charge density near the sharp points and the electric field near them will be high. This can ionise the surrounding air and can cause the charge to leak away. Thus a charged metal with sharp points will get discharged by this action.; the corona discharge.
I’m studying induction cookers
what would happen if i placed 2 or more induction coils in close proximity (say a cm apart) and turned them all on?
and how exactly do zoneless induction hobs work?
what would be required to negate the undesired effects, if any?
also, why do they have only circular coils? can it be rectangular/ triangular?