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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1
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1answer
32 views

conversion of units

I have two quantities thst I need to convert to different units. First, I need to note that these values are in the natural units system. Both of these quantities are in cm^-1 (or, to be accurate, ...
1
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4answers
81 views

Why aren't all points on a rolling ball moving?

If a ball is rolling down a hill as shown, what can be said about the points indicated at that particular point in motion? (A) Point A is moving to the left, Point B is at temporarily at ...
0
votes
1answer
33 views

What are the proper unit types for the calculation of the frequency of a tuning fork?

Wikipedia Article on the subject The formula states that the calculation of the frequency with cylindrical tines should be $$1.875^2/(2\pi L^2)\times(Er^2 /(4P))^{1/2}$$ where the variables are ...
-2
votes
0answers
21 views

How do I use Amperes Law to determine the instantaneous magnetic field for a time-varying currnet?

If it helps the wire is inifinte in length. Thank you. (reposted with more appropriate wording)
0
votes
0answers
23 views

How to calculate the Casimir energy of massive scalar field in 3-dimensional torus?

If the 3-dimensional torus's three edges are $a,b,c$, and mass of the scalar field is $m$, how to calculate the Casimir energy of this space? I know how to calculate the massless case, while the ...
1
vote
1answer
33 views

How to predict bound states in a 1 D triangular well?

Assume we have a (single) particle in a potential well of the following shape: For $x \leq 0$, $V = \infty$ (Region I) For $x \geq L$, $V = 0$ (Region III) For the interval $x > 0$ to $x < ...
2
votes
2answers
53 views

Solving the two body problem numerically

I'm trying to solve the two body problem numerically, setting up $G$, $m1$ and $m2$ to be equal to 1. then I located each mass on positions -5 and 5 respectively along the $x$ axis and gave them both ...
1
vote
0answers
11 views

How to solve this energy problem using trends related to impulse and momentum? [on hold]

The question runs a 1kg block moves with a speed of 10 m/s. It strikes a spring that has a spring constant of 25 N/m. Determine the maximum compression of spring. The energy way of solving ...
0
votes
0answers
13 views

Find the angle when lower mass loses contact with ground [on hold]

Consider the following simplified model of a skater falling over: Two equal masses $m$ are attached to opposite ends of a light, straight rod of length 2. One mass rests at $(0,0)$ on a ...
-3
votes
0answers
14 views

magnetic field of bar magnet

two bar magnet each of magnetic moment M are hang through mid point of each. such that both are perpendicular to each other . find the magnetic field at the line which is angle bisector of the two ...
0
votes
1answer
32 views

Increase of an electron's (relativistic) mass

Considering the equivalence of mass and energy, is we want to increase the (relativistic) mass of an electron 1000 times, should we give it 5*10^5 * 1000 = 5*10^8 eV of Kinetic energy => 1001 electron ...
1
vote
2answers
247 views

How does a rocket's exhaust gas' momentum propel a rocket?

During the launch of a rocket into space, the exhaust gases from the engine possess momentum. Outline, with the help of an equation, how this causes the rocket to be propelled upwards. Can ...
0
votes
0answers
22 views

Future causality of Dirac charge current spinor

I am trying to solve following problem: The Dirac equation reads \begin{equation} \nabla^{AA'} \psi_{A} = \mu \chi^{A'}, \quad \nabla_{AA'} \chi^{A'} = -\mu \psi_{A} \end{equation} where $ \mu ...
0
votes
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
vote
1answer
45 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
46 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
votes
2answers
34 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
votes
1answer
54 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
57 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
votes
0answers
32 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 ...
-7
votes
1answer
43 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
59 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
16 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
vote
0answers
59 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
49 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
votes
2answers
42 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
vote
0answers
46 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
votes
0answers
20 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 ...
-4
votes
0answers
21 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
votes
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
32 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
votes
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
votes
3answers
37 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
vote
1answer
41 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
votes
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
73 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
54 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
1answer
78 views
+50

Velocity profile of a viscously damped wave

For a test case, I want to determine the velocity profile of a viscously damped standing wave. By linearizing the density ($\rho=\rho_0+\rho'$) and velocity ($ux=ux'$), the continuity and ...
-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
63 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
votes
0answers
38 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.