Applies to questions of primarily educational value - not only questions that arise from actual homework assignments, but any question where it is preferable to guide the asker to the answer rather than giving it away outright. Please READ THE GUIDANCE IN META before asking homework-like questions.

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0
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0answers
17 views

The difference between $R(r)$ vs $r$ graph for $4s$ and $5p$ orbital

Both orbitals have equal number of radial nodes (number of radial nodes = $n-l-1=3$). So the curve cuts the $x$-axis in 3 points. If it was $\psi^2$ vs $r$, then the curve would touch the $x$-axis at ...
1
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1answer
11 views

For infinitesimal Canonical Transformations, what functions are allowed for this to be a canonical transformation?

Consider two infinitesimal transformation: $$q_{i} \rightarrow Q_{i} =q_{i} + \alpha F_{i}(q,p) $$ $$p_{i} \rightarrow P_{i} = p_{i} + \alpha E_{i}(q,p) $$ where $α$ is considered to be ...
0
votes
1answer
44 views

How to understand tedious tension questions

A rope is wrapped $M$ whole turns round a cylindrical post, the two ends of the rope going in opposite directions. The coefficient of the friction between rope and post is 0.25. It is desired that ...
0
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2answers
32 views

Does the spring effect a moving ball? [on hold]

There is a ball attached to spring which is streched out. The ball is held by a machine on the ground so it does not move, but when it is released it will quickly contract. At the same time a ...
0
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1answer
53 views

Is the formula, for finding the distance between two slits, my books gives correct?

In my book'a section on Young's double-slit experiment, the formula, $d = m \lambda \sin\theta$, is given. In this equation $d$ is the distance between two slits, $\lambda$ is the wavelength of light ...
0
votes
1answer
29 views

Finding the V(speed) of a 12KG bucket in pulley with the law of conversation of energy [on hold]

A system of two paint buckets connected by a lightweight rope is released from rest with 12kg bucket 2m above the ground floor. Use the principle of conservation of energy to find the speed with which ...
0
votes
3answers
56 views

A ball moves in the radial groove of a rotating disk [on hold]

As shown in the figure above, a ball can fit perfectly and move freely in the radial groove of a disk. There is no friction in the groove. We do not consider gravity here (or think the disk surface ...
0
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0answers
30 views

Proof of relativistic kinetic energy [on hold]

In the picture there is a proof of what the difference in kinetic energy is for a particle under a force $\vec{F}$ in relativistic mechanics. The derivation is given in terms of seven steps. 1)The ...
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1answer
37 views

Which makes an electromagnet stronger? AC or DC? [on hold]

I need a clear answer and a good explanation about this. Please tell me what happens with an AC or DC current. I have already read a lot of books but I did not get this at all. So please tell me: ...
0
votes
1answer
39 views

Particle constrained to move in a sphere? [on hold]

A particle of mass $m$ rests on the top of a smooth (frictionless) sphere of radius $R$. The particle is disturbed very slightly so that it starts to slide off the sphere, and its position can e ...
-3
votes
1answer
58 views

Is the sum of mass of all planets in our solar system is 40% the mass of the Sun? [on hold]

According to Chandrasekhar Limit, the mass of an object can not exceed than 1.4 times the mass of the sun. But according to some other theories, the sun was very large at former times and earth and ...
-1
votes
1answer
15 views

Net force on particle 1 due to particle 2 - Express your answer in vector form [on hold]

I am trying to work out the correct answer for an online physics quiz, but nothing I try seems to be correct. The question is: Consider two positively charged particles, one of charge $q_0$ ...
1
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0answers
56 views

Quadratic Casimir Operator of $SO(5)$ [on hold]

In the article A Four Dimensional Generalization of the Quantum Hall Effect, arXiv:cond-mat/0110572, by Zhang and Hu Quadratic Casimir operator for $SO(5)$ is given as $$p^2/2+q^2/2+2p+q .$$ When ...
0
votes
1answer
47 views

Finding the electric field of a NON uniform slab? [duplicate]

If we have an infinite slab that is not uniformly charged and is not a conductor, how can we find an expression for the electric field everywhere? Here's a picture Things we know about the slab: ...
0
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2answers
39 views

Moment of inertia of uniform solid sphere [on hold]

I have derived moment of inertia of solid sphere along diameter but my textbook says that moment of inertia is: $$\frac{2MR^2}{5}$$ What is the mistake in my derivation?
1
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0answers
44 views

Existence of affine parametrization [on hold]

This is a question from General Relativity by Wald Chapter 3, problem 5. Given either pseudo-Riemannian or Riemannian metric $g_{ab}$ and manifold $M$. Assume the $\nabla$ is compatible with the ...
0
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0answers
19 views

Viewing tube light through small cracks

This question appeared on a test: If you peer through very small cracks between your fringes at a tube light some distance away will you see interference patterns, Fresnel patterns or Fraunhofer ...
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0answers
20 views

PROBLEM RELATED TO HARE'S APPARATUS [on hold]

while using hare's apparatus , ratio of specific gravities of two liquids A and B was found to be 1:4 respectively. the differences in the levels of liquids A and B in the tube were found to be 16cm. ...
-2
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0answers
17 views

Maximum angle of a prism to have an emergent ray [on hold]

the critical angle of the prism ABC is 40degree. for a ray of light incident on AB , to emerge from the face AB , what should be the maximum value of angle A? please explain how to do this ...
-1
votes
1answer
31 views

For a projectile to cover maximum vertical distance in the least time, what will be the angle of projection? [on hold]

My first guess was 90° as there is no horizontal component for velocity when the angle is 90°. But I could not prove it mathematically (and also I'm not sure if it is really 90°).
-1
votes
1answer
40 views

How is the final velocity in 2 body collision distributed between the 2 bodies?

Suppose 2 sphere of mass 1Kg move with velocity 5m/s and 10m/s in same direction. Let us call the ball moving with 5m/s blue and other one red with blue ahead of red from origin. Initial KE of Blue = ...
-1
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0answers
10 views

Energy Transfer Equation - Geothermal water energy [on hold]

I'm a student of Integrated Water Management, so not physics trained, but attempting to solve this question with your help. I have a bore with geothermal water exiting at an average annual ...
0
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3answers
36 views

Drag force - dimensional analysis

I have tried the following example from the link: MIT OCW 8.012 PS1 It is about dimensional analysis. Derive an expression for the drag force on a ball of radius $R$ and mass $M$ moving with ...
-2
votes
0answers
21 views

Magnetic field at focus of parabola [on hold]

A parabola in $x$-$y$ plane carries current $I$, find the magnetic field at the focus of the parabola. Assume focus is at the origin and the focal length of parabola is $d$.
-1
votes
0answers
29 views

How do you make a diagram for this vector problem? [on hold]

Question: The simple sum of two co-initial vectors is 16 units and the vector sum is 8 units. The resultant of the vector of the vectors perpendicular to the smaller vector. Find the magnitude of the ...
1
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1answer
39 views

How a paper plane(rocket) flies in air? what is science behind it? [on hold]

What factors helps a paper plane to fly and can you explain how these factors help the plane to fly?
-2
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0answers
13 views

What is the wavelength of the light and how far away from the central maximum are the first and second maxima? [on hold]

A single, monochromatic light source is shined through an etched, flat prism with a slit separation of 0.025mm. The resulting interference pattern is viewed on a screen 1.25m away. The third maximum ...
0
votes
1answer
72 views

How is angular momentum conserved?

A uniform vertical turntable (mass M and radius R center O) is at rest on the xy plane and is mounted on a frictionless axle, which lies along the vertical z axis. I throw a lump of putty mass m with ...
-2
votes
0answers
18 views

What is the small angle measurement from the central maximum to the first maximum? [on hold]

Two thin slits with separation of 0.0200mm are placed over monochromatic red laser of wavelength 632nm. What is the small angle measurement from the central maximum (zero degrees, in-line with source) ...
-1
votes
3answers
52 views

Figure out the force constant of a spring [on hold]

You are asked to design spring bumpers for the walls of a parking garage. A freely rolling 1200-kg var moving at 0.65m/s is to compress the spring no more than 0.090m before stopping. What should be ...
-3
votes
0answers
59 views

Speed and gravity increase rate [on hold]

I'm writing a runner game where the player is always moving forward at a certain speed with a few ramps to jump. The speed of the player will increase a certain % every frame, e.g. ...
3
votes
2answers
34 views

Force on non-moving charge in solenoid with increasing magnetic field

The problem: "Through a solenoid there is an increasing magnetic field $B$. For a positively charged particle not in motion, what is the direction of force on the particle?" Normally a non-moving ...
0
votes
1answer
60 views

Is there a formula/relationship between $q$, $m$, $c$, $\Delta T$ and $t$ (time)?

I am currently doing an experiment where I am burning methanol to test for the heat of combustion. To test this, I am heating 100g of water and raising it by 20 degrees Celsius before extinguishing ...
-4
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0answers
37 views

Newtonian motion in vacuum

A spaceship is moving with constant acceleration in space. suddenly its fuel gets exhausted. Will it continue to move with constant acceleration and its velocity keep on increasing?
-2
votes
0answers
9 views

Find the total energy stored in the network at the time of steady state? [on hold]

Find the total energy stored in this network at the time of steady state.
-1
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0answers
25 views

Three blocks on inclined plane problem [on hold]

I came across this problem on physicsgalaxy.com. My approach: Found limiting friction between 30 kg and 50 kg as 72 N. Found limiting friction between 50 kg and 40 kg as 256 N. Now P+50 sin(37) ...
0
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0answers
59 views

Vibrating water container problem

I am struggling with visualising and understanding the phrasing of this question - cross posted from Math stack exchange since this forum is more appropriate: "A water-filled container is ...
1
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1answer
27 views

can any one please explain in simple terms phase change of reflected light

Phase change is used to explain interference in thin films . The concept is not explained there . Does the change in direction by 180 mean phase change ?
0
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2answers
49 views

Electric field in a non-uniformly charged sheet [on hold]

So if we have a large sheet that is not uniformly charged and is NOT a conductor, how can I find an expression for the electric field everywhere? Things we know about the sheet: the width is 2b it ...
0
votes
1answer
88 views

How long will it take before the orbit of the earth is 365 days exactly?

I understand that the number of days per year has changed throughout the history of the Earth. Apparently there were once over 400 days per trip around the sun. How long will it take approximately ...
0
votes
0answers
29 views

How to calculate force needed to launch an object of known mass vertically? [on hold]

I am going to contract a spring and release it to project an object of known mass to a specified distance upwards(vertically).I want to calculate the needed force to overcome gravity and reach the ...
-1
votes
0answers
60 views

How do I calculate momentum for a particle in a box, using the momentum quantum operator? [on hold]

For a particle in a one dimensional box with $U(x) = 0$ between $x = 0$ and $x = L$ (infinite Potential well) the momentum for $n = 1,2,3,...$ is given by: $$p_n = \frac{nh}{2 L}$$ The wave ...
1
vote
0answers
31 views

Variation of quadratic term in modified Einstein-Hilbert actions

In the context of mimetic gravity at some point one try to add to an already modified Einstein-Hilbert action also a term like $$ S_\chi=\int\,d^4x\,\sqrt{-g}\frac{1}{2}\gamma\chi^2,\qquad(\star) $$ ...
0
votes
1answer
31 views

Slingshot Energy into traveled distance [on hold]

If I have a slingshot and I am told that when pulled it has about $E$ joules of energy, how do I compute the height at which an object of mass $m$ would travel if the slingshot is released in the ...
-3
votes
1answer
36 views

Question to find distance at which 2 trains will pass each other [on hold]

I was solving some questions related to motion, and I came through a question which I cant understand. The question goes like this: Two trains A and B, 100 km apart are approaching towards each ...
1
vote
2answers
95 views

Proof of Archimedes Principle

Say I have an arbitrary body $\Omega$ and surface $\partial \Omega$ submerged in a hydrostatic fluid of density $\rho$ under the influence of gravity. How does one show Archimedes Principle? i.e. ...
-6
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0answers
30 views

Particle Physics [on hold]

Which of these statements are true? A. temperature becomes very high during this process. B. pressure becomes very high in this process C. fission fragments are radioactive D. alpha-rays are ...
-1
votes
0answers
39 views

Proof of Poisson equation in a gravitational field [on hold]

Can anybody show me how to prove Poisson's equation in Newtonian Gravitational field?
-2
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0answers
23 views

Effective mass in a Bohr atom [on hold]

I was solving a question in a hypothetical situation, in which a carbon atom consists of 6 pions instead of an electrons. Acoording to Bohr model of an atom, what would be the ground state energy of ...