# Search results

1. ### Why Groundwire at the Centre of Electricity pylon?

We have noticed in various electricity pylons/towers that groundwire or shieldwire is always placed at the top and between the two conductors ? why is that so? If you look at the 220kV structures or 500kV structures of pylons, you will notice the groundwire is placed at the middle of...
2. ### 2y'-(x/y)+x^3 cosy = 0 solve?

Homework Statement Solve the follwing differential equation 2y'-(x/y)+x^3 cosy = 0 solve? Homework Equations Linear Differential equation: y'+py=q exact differential equation: Mdx+Ndy=0 The Attempt at a Solution both of the methods i have applied .... but didnt work later i...
3. ### The value of spring constant in Mass spring system in an elevator

A mass spring system is in elevator which moves upward with an acceleration "a" . What will be effect on the measured value of spring constant compared to its value when elevator is at rest. Since K= F/x At rest F=mg But with acceleration F=m(g+a) So I think the value is...
4. ### Bernoulli principle or due to Viscosity?

Why the speed of water in the middle of the smooth flowing stream is high than its speed on the sides? Is it due to Adhesion or cohesion forces or viscosity or Bernoulli principle holds here? Kindly tell me exact reason .
5. ### Amount of Energy from Bullet fired from different weapon

How we differentiate the amount of Energy of a bullet fired by a gun and a rifle with same linear velocity? do they posses the same energy ? or rifle has more energy than gun.
6. ### Law of conservation of momentum problem?

Homework Statement A man of mass 65kg is running at speed of 4.9m/s, jumps in to a rowboat of 88kg that is drifting without friction in the same direction at a speed of 1.2m/s. when the man is seated in the rowboat, what is the final velocity of the boat? Homework Equations Momentum...
7. ### Newton's Third law of motion problem.

Homework Statement An object is free to move on a table, ex- cept that there is a constant friction force f that opposes the motion of the object when it moves. If a force of 10 N pulls the object across the table, the acceleration is 2 m/s2. If a force of 20 N pulls the object across the...
8. ### Calculate the work done in Rectangle?

Homework Statement A force acting on a particle moving in XY plane is given by F= 2y i + x^2 j . particle moves from origin to a final position having coordinates (x,y)=(5,5). calculate the work done by force F along B_____________C | | |...
9. ### Why work is a scalar quantity? explain it: not by dot product but by giving reasons?

We know that work is the dot product between force and displacement .. so dot product always gives scalar (horizontal projection etc) hence work is a scalar quantity? I want the reason behind it..... we always do work in specific direction.. suppose a man in appliying force at the...
10. ### What if Jacobi Method's condition did not met?

what if Jacobi Method's condition did not meet? Homework Statement solve by Jacobi Method upto four decimal places 8x+y-z= 8 2x+y+9z= 12 x-8y+12z = 35 Homework Equations The Attempt at a Solution since the condition of convergence of jacobi method is |A1| > |B1|+|C1|...
11. ### The ambiguous question came to my last week exam

Homework Statement If f(x) = x^3, show that f(a,b,c) = a+b+c Homework Equations I have given exam last week. and i am still searching for this question .. what this is about. is it from Tensor coordinate transformation or some numerical analysis involve here. kindly somebody...
12. ### How to find Particular integral of this differential eq:

Homework Statement Solve the following differential equation y'''-3y''+2y' = e^x/(1+e^(-x)) Homework Equations The Attempt at a Solution first i find the complementary function i-e Yc= C1 e^x + C2 e^(1+√3)x + C3 (1-√3)x now i started to find particular integral by Yp =...
13. ### Surface integral or Divergence Theorem confused?

Homework Statement Find the Volume ∫∫ xy DA where R is the region bounded by by the line y=x-1 and the parabola y^2=2x+6. Homework Equations ∫∫ xy dx dy The Attempt at a Solution first i found the intersection of the above equations . which is (5,4) to (-1,-2) . then i...
14. ### Green's Theorem or Simple Line integral Evaluation

Homework Statement Evaluate the following line integral ∫y^2 dx + x dy where C is the line segment joining the points (-5,-3) to (0,2) and is the arc of the parabola x= 4-y^2 Homework Equations Green's Theorem ∫ Mdx + Ndy = ∫∫ (∂N/∂x - ∂M/∂y ) dy dx The Attempt at a...
15. ### The dual nature of Nabla ?

I didn't get the concept of dual or hybrid nature of nabla? I-e vector differential operator .. Is it means that nabla can produce a vector from scalar field (gradient) and scalar from vector field(divergence) ? What's the concept of Nabla's Dual nature ? Please explain..
16. ### Vectors differentiation formulas for Dot and Box Product! how?

Let A ,B and C represent vectors. we have 1) d/dt (A . B) = A. dB/dt + dA/dt .B 2) d/dt [ A . (BxC) ] = A . (Bx dC/dt) + A . ( dB/dt x C) + dA/dt . (B xC) now the problem in these formulas is that we know that Dot product between two vectors and Scalar triple product of vectors is...
17. ### Differential equation dx/x(z-2y^2) = dy/y(z-y^2-2x^3) = dz/z(z-y^2-2x^3)

Homework Statement Solve dx/x(z-2y^2) = dy/y(z-y^2-2x^3) = dz/z(z-y^2-2x^3) Homework Equations The Attempt at a Solution i got one solution by taking dy/y(z-y^2-2x^3) = dz/z(z-y^2-2x^3) dy/y= dz/z integ: to bothsides ln y = ln z + ln c ln y = ln (zc) y=zc y/z=...
18. ### Linear Differential Equation to solve?

Homework Statement this is Cauchy's LDE.. someone help me to solve this equation. x^2 y'' + 3x y' + y = 1/(1-x)^2 Homework Equations The Attempt at a Solution i started it with substituting x= e^t then ln x = t and d/dt = D hence the equation becomes { D(D-1) +3D +1} y =...
19. ### Theory of relativity challenged

What would happen if Theory of relativity is abolished or challeged? As the news is coming that Neutrino is supposed to cross the speed of light , what would happen to the physics laws when this discovery proved by scientists. Plz give some examples .. Of physics laws .. Which physics laws...
20. ### Homogeneous DE solution?

xcos(y/x)(ydx+xdy) = ysin(y/x)(xdy-ydx) I have started to it by Letting y=vx And then Find it's derivative put their in equation . But the equation afterwards cannot come for finding suitable integral. Kindly help.
21. ### Separating variable DE to solve

cos(x+y)dy=dx I have tried to solve it by Letting t = x+y But it's not going to be separated.. Some one plz help..
22. ### Jacobi Vs gauss-seidel

How we prove that rate of convergence of gauss-Seidel method is approximately twice that of Jacobi iterative method without doing an example itself ? What's the general proof of this statement ? I didn't fin in any book ? Can anyone plz help me ?
23. ### Distance Protection

Why Distance( Impedance) protection is always preffered in the Transmission Lines protection? As for as Short TL is concern, Sometimes we use distance as well as differential protection, but in Medium and Long Transmission Lines only Distance protection is used .. why is it so? whats the...
24. ### Earth rotation

If I just jump in the sky and will stay for 24 hours by any means, will i make a round of whole world in 24hr? As the Earth rotates in 24 hour. and if i jump in the open sky and will stay there for 24 hours by any means(helicoper or personal rocket) .. will i make a round of whole world ...

Homework Statement the capital letter option was the answer that i have chosen in my test. Homework Equations The Attempt at a Solution 1. The areas under the hysteresis loop is proportional to a) Magnetic energy density b) Thermal energy per unit volume C) ELECTRIC...
26. ### Multiple choice for checking

Homework Statement Somebody plz check my multiple choice questions, I have attempted in my exam. The capital letter is the answer that I have ticked in the exam. Homework Equations The Attempt at a Solution 1. The angular momentum of a particle under the influence of a...
27. ### Magnetic Field Density?

Homework Statement A solenoid has length L= 1.23m , and inner diameter d=3.55cm. it has five layers of windings of 850 turns each and carries a current i = 5.57 A. what B at its centre? Homework Equations B= Uo N I /L where Uo is permeability of free space. The Attempt at a...
28. ### De broglie explanation?

This question appeared in my exam . Q. A bullet of mass 41g travels at 960m/s. what wavelength can we associate with it? why does the wave nature of the bullet not reveal itself though diffraction effects? Ans.. i find de broglie wave length by formula lamda = h/mc but didnt...
29. ### Why I, J, K ?

Why Unit vectors are represented by I, J and K ? Why do unit vectors I, J and K have no units? are the unit vectors in the cylindrical and spherical coordinates system constant vectors?
30. ### Speed Vs Acceleration

Can an object be increasing in speed as its acceleration decreases? if so, give an example; if not explain why.