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Catalogs Discussion Forums -> Algebra -> does anyone dare 2 solve this??????????!!!!!!!!!!!!!!!!!!!!!!!!!!!! -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Check the third step. There should be a 2 there
Catalogs Discussion Forums -> Algebra -> does anyone dare 2 solve this??????????!!!!!!!!!!!!!!!!!!!!!!!!!!!! -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Plz make sure u didn't forget to include the limits of integration in Q2
Catalogs Discussion Forums -> Algebra -> func -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Well I went way wrong with that. Sorry dude ... the occasional slip !
The number of ways in which each element in the domain can be linked to either of the two elements in the co-domain = 2n
Now, there are two possibilities that we must overrule to make it onto, that no element in the co-domain is devoid of a pre-image. The above linkings will have 2 such cases, when either one of the elements in the codomain  is unlinked.
So total number of onto functions = 2n -2

Catalogs Discussion Forums -> Algebra -> Find n. -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Excellent solution Vinu
Catalogs Discussion Forums -> Mechanics -> find it out -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

Catalogs Discussion Forums -> Mechanics -> find out the time -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
For the ball thrown up
-h = ut1 - (1/2)gt12
h = -ut1 + (1/2)gt12 --------(1)

For the ball thrown down
-h =- ut2 - (1/2)gt22
h = ut2 + (1/2)gt22 --------------(2)

For the freely falling ball
-h = - (1/2)gt2 -----------(3)

Multiply (1) by t2 & (2) by t1 and add
h(t1 + t2) = (1/2)gt1t2 ((t1 + t2)
Cancelling (t1 + t2) and substituting the value of h from (3)
(1/)gt2 = (1/2)gt1t2
t = t1t2
Catalogs Discussion Forums -> Mechanics -> Conservative or Nonconservative force -> Go to message
This Post 10 points    (Olaaa!! Perrrfect answer.   in 2 votes )   [?]
Start from rest.
Keep applying the force and move in a closed path.
If the force is conservative, it won't do any work & by work energy theorem, there will not be any change in KE. So when you reach the starting point your particle will again be at rest.

If this doesn't happen, the force in non conservative.
Catalogs Discussion Forums -> Mechanics -> find it out -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Sneha has decided that she won't rate me!!!
Catalogs Discussion Forums -> Mechanics -> How much is the force created due to the motion of the falling chain ? -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
The answer given in the book seems to be incorrect. My approach is a bit different from urs.
The left portion of the string is a variable mass system in which mass is entering.
By Merchersky's equation,
m(dv/dt) = Fext + urel (dm/dt) = Fext + urel (dm/dx)(dx/dt)
As the left portion of the chain is in equilibrium,
= {T-(m/L)[(L/2)+(x/2)]}j  +(- 2gxj)(m/L)( 2gx)
T = (mg/L)[(L/2) + (5x/2)]
    = (W/2)[1+(5x/L)]
Catalogs Discussion Forums -> Mechanics -> find it out -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
This problem is best solved by a v-t graph


The slope of the first line is 'a' and that of the second is "-b"
Let the maximun velocity be vm
Then, vm/T = a vm/a = T ---------(1)
& vm/t-T = b vm/b = t-T ---------(2)
Adding (1) and(2)
vm = abt/(a+b)

As the v-t graph is entirely above the t axis,
So distance travelled = Displacement = Area under v-t curve = (1/2)vmt
=abt2 /2(a+b)

Catalogs Discussion Forums -> Mechanics -> pseudo force -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Let the bottom of the inclined plane be the origin of a polar coordinate system
 Then
d2 r/dt2 = -gsin
d/dt = w
dr/dt = 0t (-gsin )dt = g0t sin(0 + wt) dt = (g/w)[1-cos(0 + wt)]
where 0 is the initial angle of incline.
Acceleration of the block
a = (d2 r/dt2 - r(d/dt)2 )er + (2(dr/dt)(d/dt) + r (d2/dt2))e
    = -(gsin + rw2)er + (2(g/w)[1-cos(0 + wt)]w + r (dw/dt))e
    = -(gsin + rw2)er + (2g[1-cos(0 + wt)] + r (dw/dt))e
Catalogs Discussion Forums -> Mechanics -> freefall-1 -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Does this help??
Catalogs Discussion Forums -> Mechanics -> freefall-1 -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
5h/9 is the distance travelled in the last one second and not upto T-1th sec

So distance travelled till T-1 th sec = h - 5h/9
Community shelf Community shelf -> Projectiles continued -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]

Now, lets see one more application of the formulas developed in the previous article.
Most of you must have come across the problem
Two projectiles have the same range R and heights H1 & H2 . Prove that
R = 4 H1H2
Those of you who haven't solved this before try to do it. After you have broken your heads, or managed to solve it, come and see this solution.
As the ranges are same, they are projected at say, and 90 -
4H1 = Rtan
4H2 = Rtan(90-) => 4H2 = Rcot
then,
16H1H2 = R2
R = 4 H1H2

Community shelf Community shelf -> Some more on projectiles ... A few shortcuts -> Go to message
This Post 15 points    (Olaaa!! Perrrfect answer.   in 3 votes )   [?]

We all know the standard formulas for range, height and time of flight of a projectile. Consider a problem like this
A particle projected obliquely at 45 deg has a range of 16m. Find the maximum height reached by the particle.
Standard procedure:
Write the formula for Range
Evaluate u.
Find H.
Time taken: 2 min
Lets do summa new.
R = u2 sin2/ g
H = u2 sin2 / 2g
R/H = 4/tan
4H = Rtan
Use this relation
4H = 16 tan45
H = 4
Time taken :5 s
You get the idea. Similarly by doing R/T2 , H/T2 we get the following set of formulas
4H = Rtan
Rtan =(1/2)gT2
H =  (1/8)gT2
Now try solving these problems:
1. The range of a particle thrown at 45 deg is 8m. Find the time of flight.
2. The maximum height reached by a particle thrown obliquely is 2m. Find its time of flight.
Try solving these without using these simplifications once. You'll never let go of these then

Catalogs Discussion Forums -> Optics -> optics -> Go to message
This Post 2 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
If you want to understand HOW this occurs, Huygens construction (given in every standard textbook) will prove useful.
Light is an electromagnetic wave comprising of electric and magnetic components. We usually study light using the electric component. In higher physics, reflection & refraction can be explained in terms of this electric vector. But don't try to break ur head trying to understand this. Read up Huygen's construction. That should be fairly good explaination
Catalogs Discussion Forums -> Differential Calculus -> The limit paradox -> Go to message
This Post 12 points    (Olaaa!! Perrrfect answer.   in 3 votes )   [?]
The addition on the left hand side makes sense only if x is an +ve integer, for we can add something to itself only in steps of +ve integers
So the sum = x2
But the graph of this function will be a collection of points at integral values of x
So the sum isn't differentiable.
Thats the fallacy ...we are differentiating something that is non differentiable
Catalogs Discussion Forums -> Thermal Physics -> calculate heat transfer( plz mechanical engg students) urgent ! -> Go to message
This Post 0 points    (Olaaa!! Perrrfect answer.   in 0 votes )   [?]
Are you sure of the relevance of this question??? Where did u pick it up?
Catalogs Discussion Forums -> Coaching Institutes & Course Material -> bookssss---GET SALUTES FOR FREE -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
Well bro ... if you have done all the books you say you have done, you don't need to worry. Best strategy is to review the work you have done, identify you weak areas and work on them.
Get any previous year question bank. Work it out thoroughly. That should help a lot.
Catalogs Discussion Forums -> Integral Calculus -> integrationnnn -> Go to message
This Post 5 points    (Olaaa!! Perrrfect answer.   in 1 votes )   [?]
1)
{1/[3+(8tan(x/2) / (1+tan2(x/2))]} dx
{sec2(x/2)/[3+3tan2(x/2)+(8tan(x/2) ]} dx
Substitute tan(x/2) = t
2{1/[3+3t2+8t]} dt
(2/3) {1/[t2+ 8t/3 + 1]} dt
(2/3) {1/[(t + 2/ 3)2- (1/ 3)2]} dt
(2/3)(1/2 3)ln[( 3t + 3)/( 3t + 1)]
(1/3 3)ln[( 3tan(x/2) + 3)/( 3tan(x/2) + 1)]
 
 
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