IIT JEE , AIEEE Forum - Physics , General

kane

if you want to memorize the members of 14 th group learn this sentence:

Cousin Sister ji suno problem

C implies carbon

Si implies silicon

ji sounds same as Ge which is germanium

suno for Sn which is antimony

problem for Pb which is lead

kindly rate

kane

now for group 15th elements:

Nana Patekar Aaj se Sabji Bechega

N-nitrogen

P-phosphorus

As-arsenic

Sb-antimony

Bi-bismuth

cheers!!!

rate if useful

kane

if a normal chord of a parabola intersects at two pts. of the parabola whose parameter is given by t₁ and t₂ resp. then t₂= -t₁ - 2/t₁

this result is true for every parabola

kindly rate if useful

shubham.123

analytical chemistry
crgr : Cr green all compounds of cr r green
(cro3 is exceotion )

mukulss

i have rated everyone is it not.

kane

if the angle of an inclination is changed keeping the height constant then the ratio of times taken to travel the inclined plane in two different cases is inversely equal to sine of the angles.

i.e. t₁/t₂ = sin

₂/sin

₁

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learner

If a body accelerates uniformly from rest,

moves with uniform velocity for a while ,

and then

decelerates with the same magnitude,

time of motion when velocity is uniform is given by :

(t²-4s/a)^0.5,

where : t =total time of flight

s=total distance covered

a = acceleration

mukulss

@learner that is good.
but it is better if u can prove it too 4 all

learner

Sure!!

t1=time of acc

t2=time of uniform velocity

Distance moved with constt. acc=Distance moved with constt. retardation..

=0.5at1²

Adding both,we get at1^2

Distance moved with uniform velocity=s-at1^2 ....(s is total distance)

v = s-at1^2 ....v= uniform vel.

Thus,

t2 = (s-at1^2)/v

but,v =at1...coz u = 0,

Let t be total time,

thus,

t2=(s-at1^2)/at1

Hence,

s-at1^2=at1t2 ...........eq 1

Now,

t=2t1 +t2

Substituting values from eq1,

s - (1/4)a(t-t2⁾²

^{(NOO!!!SUPERSCRIPT IS STUCK AGAIN!!!!!!!!)}

learner

Sorry,the other side of that eqn is:

(a(t-t2)t2)/2

Thus,

s=(a(t-t2)/2) (t2+ (t-t2)/2 )

Simplify,you get:

t2^2= (at^2-4s)/a

Simplifying and taking root,we get the result...

If any doubts,nudge pls!!

kane

whenever a body is projected upwards from a building and we are required to find the total time it takes to reach the ground i.e. time taken to reach the highest pt.+ time taken to fall on ground is given by

t= -ut+ 1/2 gt²

this is the short method.in the longer method you will have to find the different times individually!!!!

rate if useful

shevchenko

SN1 mechanism where the reactants of first step react back to give optically inactive product

mukulss

@ shevchenko.
though i hav erated u but i think u must re read my topic.
it says short and easily undestandable concepts.
please try 2 explin what u r actualaly triyng 2 say friend.

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