| Message |
|
|
when the block is shifted by a distance x along the spring c it is acted upon by 3 forces of a b and c
for a restoring force(f1)=kx
for b f2=kx cos45
for c f3=kx cos 45
the resultant of f2 and f3 is along f1
R2,3=underroot(k^2x^2cos^45+k^2x^2cos^45 +o)=kx
[f2 and f3 are perpendicular to each other]
therefore total restoring force=kx+kx=2kx
which is proportional to x, therefore s.h.m
now
2kx=mw^2x
w^2=2k/m
T=2pie /underroot(w^2)
=2pie underroot(m/2k)
|
|
|
|
A penny dropped from the top of a tall building could kill a pedestrian
A penny isn't the most aerodynamic of weapons. A combination of its shape and wind friction means that, tossed even from the 1,250-foot Empire State Building, it would travel fast enough merely to sting an unlucky pedestrian.
|
|
|
|
well i can explain the graph of sin2x.
this graph would have the same range but domain would be half that of sinx that is 2pie/2=pie hence the graph of sinx is the graph of sin2x only but within 0-pie
|
|
|
|
no now i think it is 4 only
by the method greatdreams used only-sin2x=+-1/underroot 2
and not only positive value hence we will get four values on drawing the graph
|
|
|
|
|
|
Red Rain Could Prove That Aliens Have LandedThere is a small bottle containing a red fluid on a shelf in Sheffield University?s microbiology laboratory. The liquid looks cloudy and uninteresting. Yet, if one group of scientists is correct, the phial contains the first samples of extraterrestrial life isolated by researchers.
Inside the bottle are samples left over from one of the strangest incidents in recent meteorological history. On 25 July, 2001, blood-red rain fell over the Kerala district of western India. And these rain bursts continued for the next two months. All along the coast it rained crimson, turning local people?s clothes pink, burning leaves on trees and falling as scarlet sheets at some points.
Investigations suggested the rain was red because winds had swept up dust from Arabia and dumped it on Kerala. But Godfrey Louis, a physicist at Mahatma Gandhi University in Kottayam, after gathering samples left over from the rains, concluded this was nonsense. ?If you look at these particles under a microscope, you can see they are not dust, they have a clear biological appearance.? Instead Louis decided that the rain was made up of bacteria-like material that had been swept to Earth from a passing comet. In short, it rained aliens over India during the summer of 2001.
Not everyone is convinced by the idea, of course. Indeed most researchers think it is highly dubious. .
But a few researchers believe Louis may be on to something and are following up his work. Milton Wainwright, a microbiologist at Sheffield, is now testing samples of Kerala?s red rain. ?It is too early to say what?s in the phial,? he said. ?But it is certainly not dust. Nor is there any DNA there, but then alien bacteria would not necessarily contain DNA.?
Critical to Louis?s theory is the length of time the red rain fell on Kerala. Two months is too long for it to have been wind-borne dust, he says. In addition, one analysis showed the particles were 50 per cent carbon, 45 per cent oxygen with traces of sodium and iron: consistent with biological material. Louis also discovered that, hours before the first red rain fell, there was a loud sonic boom that shook houses in Kerala. Only an incoming meteorite could have triggered such a blast, he claims. This had broken from a passing comet and shot towards the coast, shedding microbes as it travelled. These then mixed with clouds and fell with the rain. Many scientists accept that comets may be rich in organic chemicals and a few, such as the late Fred Hoyle, the UK theorist, argued that life on Earth evolved from microbes that had been brought here on comets. But most researchers say that Louis is making too great a leap in connecting his rain with microbes from a comet.
For his part, Louis is unrepentant. ?If anybody hears a theory like this, that it is from a comet, they dismiss it as an unbelievable kind of conclusion. Unless people understand our arguments - people will just rule it out as an impossible thing, that extra-terrestrial biology is responsible for this red rain.?
source:internet
|
|
|
|
hey anandghegde
when water is in between plates the radius of curvature of water surface=r while that of the st line is infinity.hence--
excess p=T(1/r + 1/infinity)=T/r
|
|
|
|
|
|
ok perhaps now i understand. when we apply the force the area on which we would apply it =2A henc ans=2A*A/v
|
|
|
|
when water is between two plates excess pressure=T/r
=TA/V
therefor F required=TA*A/V
i don't know why this option is not there, hoping that someone will explain!!
|
|
|
|
first of all look at the last line
F = 3ma/2+ma/2+Ma = a(M+3m) ----this is incorrect itself
as it =2ma +Ma=(M+2m)a
the soln came wrong because the concept used is wrong-
here a is not equal to r*alpha
but r*alpha-a=a ie a=r*alpha/2
hope you understand!!
i don't know why you gave hsbhatt 5 pts!!!
|
|
|
|
|
Animals can rain from the sky  Raining animals is a relatively common meteorological phenomenon, with occurrences reported from many countries throughout history. The animals most likely to drop from the sky in a rainfall are fish and frogs, with birds coming third. Sometimes the animals survive the fall, especially fish, suggesting a small time gap between the extraction and the actual drop. Several witnesses of raining frogs describe the animals as startled, though healthy, and exhibiting relatively normal behavior shortly after the event. In some incidents, however, the animals are frozen to death or even completely enclosed in blocks of ice. These occurrences may be evidence for the transport of the victims to high altitudes, where the temperature is below zero, and they show how powerful meteorological forces can be. Most recent occurrences include the rain of frogs and toads in Serbia (2005) and London (1998), and rains of fish in India (2006) and Wales (2004).
In Honduras, the Lluvia de Peces (Rain of Fishes) is a unique phenomenon that has been occurring for more than a century on a yearly basis in the country of Honduras. It occurs in the Departamento de Yoro, between the months of May and July. Witnesses of this phenomenon state that it begins with is a dark cloud in the sky followed by lightning, thunder, strong winds and heavy rain for 2 to 3 hours. Once the rain has stopped, hundreds of living fish are found on the ground. People take the fish home to cook and eat them. Although some experts have tried to explain the Rain of Fishes as a natural meteorological phenomenon, the fish are not sea water fish, but fresh water fish; they are not dead, but alive; they are not blind, they have eyes; they are not big fish, but small; and the type of fish is not found elsewhere in the area. There is no valid scientific explanation for this phenomenon. Many people believe this phenomenon occurs because of Father José Manuel Subirana, a Spanish catholic missionary and considered by many to be a Saint. He visited Honduras from 1856-1864, and upon encountering so many poor people, prayed for 3 days and 3 nights asking God for a miracle to help the poor people by providing food. The Rain of Fishes has occurred ever since.
Source:internet
|
|
|
|
|
hsbhatt's soln is incorrect
|
|
|
|
|
F-T-f=Ma ----1
T-f=ma ----2
fR=I?
?=2f/mR [I=mRR/2)
also for rolling R?-a=a
therefore ?=2a/R=2f/mR
therefore f=ma
1+2----
F-2f=(M+m)a
F-2ma=Ma+ma
F=(M+3m)a
therefore a=F/M+3m
Cheers!!
|
|
|
|
|
Well what I can think is this-- the boat with scrap iron would displace more water than boat alone+scrap alone. this is because boat + scrap iron would displace water equal to volume of boat submerged without stone(v1) +due to weight of stone(v2). however when scrap iron would be thrown. boat will displace water equal to v1 and scrap iron would sink hence it will displace v3=less water than what its weight would ie v3<v2, therefore v1+v2>v1+v3, thus the water level would fall.
|
|
|
|
well taking any wave-y=asin(wt-kx)
its phase is wt-kx
if we take another wave y=asin(wt-kx+phi)
its phase is wt-kx+phi
therefore phase diff=wt-kx+phi-(wt-kx)=phi
Hoping that its helpful!
|
|
|
|
are you now clear about the derivation?
|
|
|
|
|
|
|
 |
|
E-Store
