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Catalogs Discussion Forums -> Algebra -> finding speeds.... -> Go to message
This Post 7 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]
1 replies   
Let they meet each other at distance x from B and at time t and let the total distance of journey be l.
Let the speed of second man be u.
Speed of first man = 12

When they meet :

x = 12t    and    l - x = vt

Dividing these two :  v/12 = (l - x)/x........(1)

The journey after meeting :

1st man would now cover l - x distance in 10/3 hours.
Hence l - x = 12(10/3) = 40............(2)

2nd would cover x distance in 24/5 hours.
Hence x = v(24/5).................(3)

From (1)    v/12 = (l - x)/x = 40/x
x = 480/v

Put this in (3)

480/v = v(24/5)

v2 = 480(5/24) = 100

Hence v = 10 km/hr
 


Catalogs Discussion Forums -> Analytical Geometry -> please help--- urgent !!! -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
12 replies   
m1 = -b/a    and    m2 = b/a

tan  = | (m2 - m1) / 1 + m1 m2 |

 
= tan-1[{(b/a) - (-b/a)}/{1 + (b/a)(-b/a)}]

    = tan-1{(2b/a)/(1 - b2/a2)}

    = 2tan-1(b/a)
Catalogs Discussion Forums -> Mechanics -> projectile motion -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
2 replies   
Let x-axis be along the inclined plane and y-axis be perpendicular to it.

ax = -gsin300   and    ay = -gcos300

Initial velocity :  ux = u.cos(30+)    uy = u.sin(30+)

Final velocity in x-direction is zero since it hits the plane perpendicularly.

0 = u.cos(30+) - (g.sin30)t

t = u.cos(30+)/(g.sin30) ............(1)

y-coordinate : y = u.sin(30+).t - (1/2)(gcos30)t2

When it hits the plane y = 0

t = 2u.sin(30+)/(g.cos30)..............(2)

From (1) and (2)

u.cos(30+)/(g.sin30) = 2u.sin(30+)/(g.cos30)

tan(30+) = (3)/2

= -300 + tan-1{(3)/2)

where is the angle of projection with the inclined plane.


Catalogs Discussion Forums -> Mechanics -> projectile motion -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
3 replies   
Good Work Goutham.

Horizontal component of velocity is constant.

ucos600 = vcos300

v = u/3 = 20/3 m/s

Centripetal acceleration is given by v2/R = gcos300

R = v2/gcos300 = (20/3)2/(53) = 15.4 m
Catalogs Discussion Forums -> Counselling Zone -> VERY VERY URGENT. -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
1 replies   
Concentrate on your 11th studies and take down the notes provided in your coaching. Beside coaching use remaining time to study 11th portion. And after your exams are over just go through the notes and try to grasp the topics by giving more time.
Catalogs Discussion Forums -> Algebra -> Relations -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
1 replies   
In this site there is a link named "Study Material". Click on this link and you'll get a list of various topics including Algebra.

Refer to that link and you will find the relations and their applications in examples written in very compact from.
Catalogs Discussion Forums -> Organic Chemistry -> tautomerism -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
1 replies   
Ring-Chain Tautomerism : Tautomeric forms exist in substances possessing functional groups which can interact additively and which are so placed that intramolecular reaction leads to a stable cyclic system. The cyclic form usually predominates (especially if it contains five or six members).

Keto-Enol Tautomerism : In organic chemistry, keto-enol tautomerism refers to a chemical equilibrium between a keto form (a ketone or an aldehyde) and an enol. The enol and keto forms are said to be tautomers of each other. The interconversion of the two forms involves the movement of a proton and the shifting of bonding electrons; hence, the isomerism qualifies as tautomerism.

For more information refer :

http://www.answers.com/topic/tautomerism

http://en.wikipedia.org/wiki/Tautomer

http://en.wikipedia.org/wiki/Keto-enol_tautomerism
Catalogs Discussion Forums -> Coaching Institutes & Course Material -> M.L. KHANNA OR A.DASGUPTA MCQ -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
4 replies   
M L Khanna is not that bad. You can solve some elementary problems from it just to have a start.

But I would suggest you to buy MCQ ( A Dasgupta ) which is really a good objective book. It contains a good set of problems. Must go through it.
Catalogs Discussion Forums -> Magnetism -> AC MIND BLOWING -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
5 replies   
The phase lag is given by tan = XL/R

tan = wL/R = 2fL/R = 100

Hence time lag is given by :

t = (/2)T   (T = time period)

t = [{tan-1(100)}/2](1/50)

This is approx. t = 1/200 = 0.005 sec
Catalogs Discussion Forums -> Counselling Zone -> plz experts n frenz -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
5 replies   
When there is a will there is always a way.

Your marks in board exams reflect that you are a good student , then how can you think of leaving the preparation after 1 year. You still have a year left and one year is sufficient for a good student. Means you have to show dedication throughout the upcoming year and dont be depressed because there are many who have cleared JEE form your stage. Grasp 12th topics firmly and side by side give some time to 11th topics too. All the best.
Catalogs Discussion Forums -> Counselling Zone -> query about AIEEE -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
2 replies   
The questions asked in AIEEE are not that tough but what matters is the speed on that day which can be increased by practice and solving some mock tests.

Maths : Preferably practice coordinate geometry and calculus and after completion go for sequences,complex and vectors.

Physics : Practice electricity and magnetism, mechanics , modern physics in order. Even if u r left with some time go for optics, thermodynamics and waves in order.

Chemistry : Practice whole physical part, revise concepts of organic and inorganic every morning and practice them.
Catalogs Discussion Forums -> Mechanics -> circular -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
6 replies   
Kepler's Law :

T2  R3

(T1/T2)2 = (R1/R2)3 = (R/4R)3

(T1/T2) = (R/4R)3/2 = (1/4)3/2 = 1/8
Catalogs Discussion Forums -> Thermal Physics -> Cv to molecular weight... -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
2 replies   
Cv = 0.075 kcal/(kg.K)

Suppose the molecular wt. = M

Then Cv =
(75M) cal/(mol.K)

Cv = R/(
-1)

75M = 2/(5/3 - 1)

M = 0.04 kg
Catalogs Discussion Forums -> Algebra -> QUADRATIC EQUATION -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
6 replies   
Since and are the roots of the equation ax2 + bx + c = 0

+ = -b/a       = c/a

74 + 47 = 44(3+3)

                    = ()4(+)(2-+2)

                    = ()4(+){(+)2 - 3}

                    = (c/a)4(-b/a){(-b/a)2 - 3c/a}

                    = bc4(3ac - b2)/a7
Catalogs Discussion Forums -> Physical Chemistry -> r And R -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
1 replies   
Octahedral void :

\begin{figure} \includegraphics {fig2c.ps} \end{figure}

Let a small circle squeezed between the spheres in the void and let its centre (0,0).

Distance of centre of one of spheres form (0,0) = (R2 + R2) = (2)R

Also this is equal to R + r  where r is the radius of small sphere in-between.

Hence R + r =(2)R

r = (2 - 1)R = 0.414R
 
 
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