IIT JEE , AIEEE Forum - Physics , General

kane

for circular motion we have:

1.radius vector perpendicular to velocity vector

2.radius vector antiparallel to centripetal acceleration vector

3.centripetal acceleration vector perpendicular to velocity vector

4.centripetal acceleration vector perpendicular to tangential acceleration vector

plz rate if useful

mukulss

see i have rated everyone.
is it not.

shubham.123

the most asked ques. in REC'S

if a particle go undeflected in electric and magnetic field
than its velocity ,electric field and magnetic field r perpendicular
to each other and v = E\B .............

kane

the line lx+my+n=0 is a tangent to:

1.parabola y²=4ax if am²=ln

2.ellipse x²/a²+y²/b²=1 if a²l²+b²m²=n²

3.hyperbola x²/a²-y²/b² if a²l²-b²m²=n²

kindly rate if useful

cheers

ridhima

even though the sun attracts the earth with a very large force but still it does not escape to the sun

reason - due to the force the earth is in circular motion. the falls to the sun but is taken away by the tangential velocity thus a circular motion is observed

ridhima

another one

when a fluid eg water containing some small leaves is stirred the leaves are collected at the center of the whirl and not at the edge

think

why

reason
since by stirring it the leaves gain kinetic energy, total energy must be conserved so potential energy must be reduced.
remember that in a whirl the innermost part has lower potential than the outermost part

cheers

ambareesh13

this is with regard to "shubham.123"'s post on page 3 when you mean all compounds of cr are green except cro3 then you are not including ions like chromate and dichromate bcoz i think dichromate is orange in color

tka

for problems based on center of mass, if in the question it is stated that they mutually attract each other, then without question remember that center of mass will not shift

this is because mutual attraction can be considered as an internal force

for the center of mass to change position, an external force must act on it

heavensblaze

hello everyone
here are some short cuts to permutations & combination ques.

1) ⁿC_r/^n-1C_r-1=n/r

2)ⁿP_r/ⁿP_r-1=n-r+1

Hope its useful
Cheers!!!

tarinbansal

Always remember-
1-In case of green colour the element is Cr most of the times(except CrO3)
2- In case of blood red colour, it is iron
3-In the whole Qualitative analysis, we get buff colour only at 2 places- MnS, Co(CN)2
4-Al,Sn,Zn,Pb,Cr-their their hydroxides are soluble in NaOH,their precipitates are white in colour(except Cr-green)
5-CoS,NiS,HgS -soluble only in aqua regia(AgNO3+HCl)
6-ppt of GP-II B are soluble in yellow ammonium sulphide solution while those of II A are insoluble.
7- Whenever any NH4+ salt is reacted with NaOH or KOH, NH3 is evolved.

Rate if you find this useful.

learner

If a car is moving with acceleration a,and a mass is suspended from its ceiling,

the mass swings back by an angle tan^-(a/g).

kane

if a beaker is filled with a liquid of density d upto a height h,then the mean pressure on the walls of the beaker is hdg/2

tarun_bits

in laws of motion problems ...you can consider an entact system as one...and treat it as one body

kane

when a person of mass M climbs up a rope with acceleration f,then the tension in the rope is

T=M(g+f)

when he climbs down with acc. f.tension in rope is

T=M(g-f)

Ask & Discuss Questions with Community & Experts