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0answers
11 views

Particle rotation in 3D about a point vs. an axis [on hold]

Imagine a massless rigid rod hinged at the origin $O$ of a Cartesian coordinate system. The hinge has three degrees of freedom, massless, and frictionless. At the other end of the rod is a particle. ...
0
votes
0answers
16 views

Breakdown voltage

Capacitor (Geiger counter) is made out of wire with radius $R_1 = 5 mm$ and coaxial tube with radius $R_2 = 5 cm$. What is the maximum voltage on the capacitor, given the breakdown voltage of air ...
0
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0answers
14 views

thermodynamics first law sign convention based problem

Consider a (frictionless) piston-cylinder system. Initially, one mole of an ideal gas is present in the cylinder. The pressure and temperature of the gas are 1 bar and 300 K. A stirrer slowly ...
-3
votes
0answers
35 views

Gauss Law - Variable Electric Field Perpendicular to Sheet [on hold]

So imagine a square sheet parallel to the x-y plane that has a perpendicular electric field (in the z direction) flowing through it such that $$E=\gamma x$$ where $\gamma$ is a constant value (lets ...
1
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1answer
23 views

Properties of 3D waves

I have a few questions about 3D waves: Are all 3D waves types of electromagnetic radiation? Are all 2D waves mechanical?
0
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0answers
19 views

Fraunhofer Diffraction using lenses

I've come across a question that I don't know how to tackle: An alternative way of observing Fraunhofer diffraction uses lenses to provide appropriate conditions. Sketch an optical configuration ...
0
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1answer
24 views

What is the difference between virtual object and virtual image? [duplicate]

What is the difference between virtual object and virtual image?
-2
votes
0answers
24 views

Calculating power [on hold]

I need some help and explanation with solving this question: What is the power required to give a body of mass m a forward acceleration of a when it is moving with velocity v up a frictionless ...
-2
votes
0answers
124 views

How long would it take to get to Kepler 189f?

I just read a news story about a planet that might be Earth-like called Kepler 189f. It is 500 light years away. How long would it take to travel there in a space ship, from the travelers reference ...
0
votes
1answer
32 views

Is there any significance to the negative sign on this speed?

A girl is riding a bicycle along a straight road at constant speed, and passes a friend standing at a bus stop (event #$1$). At a time of $60$ s later the friend catches a bus (event #$2$) If the ...
0
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0answers
8 views

Friction in Water - Conservation of Energy [on hold]

A 57.0 kg diver dives from a height of 15.0 m. She reaches a speed of 14.0 m/s just before entering the water. What is the force of friction underwater if she reaches a depth of 2.5 m before ...
0
votes
1answer
19 views

Conservation of Energy - A Golfer Question [on hold]

A golfer strikes a ball in a parabolic arc at and elevated green (3.5 m above launch). The ball leaves the player's club at 37 m/s and an angle of 40 degrees. The mass of he ball is 0.043 kg. ...
0
votes
1answer
8 views

Thermal resistance of thermal interface materials?

Thermal conductivity are often used for surfaces between the computer chip and the heat sink to increase heat transfer and they want high thermal conductivity to decrease the thermal resistance. By ...
0
votes
0answers
17 views

Rise of 2 liquids in a pipe [on hold]

The figure is a cross-section of a pipe of radius $r$. In the portion ABCD, a liquid of density $\rho$ is present. On the other part is present a liquid of density $\delta$. ...
0
votes
1answer
16 views

Moment of Inertia for a hollow cylinder

This question may be to rudimentary. I have found 2 formulas for calculating the inertia of a hollow cylinder. Which is correct or are they used for different circumstances? They seem to be used ...
0
votes
0answers
11 views

Charge within cavity of conductor [on hold]

A spherical cavity of radius 6.50cmcm is at the center of a metal sphere of radius 17.5cmcm . A point charge 4.20μC\mu C rests at the very center of the cavity, whereas the metal conductor carries ...
0
votes
1answer
24 views

Change of field intensity/flux density and energy

The answer for this question in the solutions manual is (D). I tried to solve it using $$ W_e = \frac12\int_\nu ED d\nu $$ Which gives me (C). Any idea where I have gone wrong?
0
votes
2answers
15 views

combination of cells

There are m*n identical cells of emf E and internal resistance r connected in parallel rows. This combination of cells is connected across an external resistance R. For what arrangement of the ...
1
vote
2answers
31 views

Ground velocity of satellite

I was wondering whether there is a simple formula in order to calculate the ground velocity (the velocity with which the satellite is moving along the planet's surface) on basis of the orbital ...
2
votes
1answer
31 views

Formula for molar specific heat capacity in polytropic process

I found this formula for a polytropic process, defined by $PV^n = {\rm constant}$, in a book: $$C = \frac R{\gamma-1} + \frac R{1-n} $$ where $C$ is molar specific heat and $\gamma$ is adiabatic ...
0
votes
3answers
19 views

Photoelectric effect. current and frequency relationship [on hold]

Does increasing the frequency of photons increase the photo-current? (keeping the light intensity constant) Is this graph correct?
8
votes
3answers
380 views

Electric Field inside a regular polygon with corner charges

If we have equal charges located at the corners of a regular polygon, then the electric field at its center is zero. Are there other points inside a polygon where the field vanishes? The simplest ...
-1
votes
0answers
11 views

Modern Optics (Fowles) Transmittance as a function of wavelength [on hold]

I need to get the coefficient of finesse to equal ((n^2-1)/(2n))^2 from 4R/(1-R)^2 knowing that the incident beam is normal so that R=((n-1)/(n+1))^2. If this isn't possible I'm not understanding the ...
0
votes
0answers
14 views

charge on a capacitor [on hold]

capacitor C1 of 1mF is charged to 100v(i.e. charge on it is 100mc).it is discoonected from the battery and connected to capaciotr C2 of 2mF .on plate of C2 is earthed .calculate the charge on each ...
0
votes
0answers
28 views

Ground state of spin in magnetic field

I am trying to solve a time dependent perturbation theory problem, and it involves the Hamiltonian $$H=-\mu B\sigma_z$$ And a perturbation $$V=-\mu B_1\sigma\cdot(\cos(\omega t)\hat x-\sin(\omega ...
1
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0answers
54 views

Volume of phase space

Consider the microcanonical description of an extreme relativistic ideal gas of $N$ particles in three dimensions, characterized by the energy-momentum dispersion $E = pc$. Compute the volume of the ...
-1
votes
0answers
14 views

For a velocity field u(x, t) r r in a fluid of density (x,t) r r , show that [on hold]

For a velocity field u(x, t) r r in a fluid of density (x,t) r r , show that
0
votes
0answers
23 views

Equivalent Force from Pressure [on hold]

I am trying to find the force at a certain point of a plate due to some pressure. I have a picture below (terribly drawn, sorry) but basically I have two plates with hinges on one side and the plates ...
0
votes
1answer
24 views

What is the eastward deflection due to Coriolis force [on hold]

Suppose, an air parcel is at the equator, and it has a northward velocity of 10 m/s. Due to Coriolis force, what is the eastward deflection of the parcel when it reaches 30N. Please show full ...
0
votes
1answer
32 views

Projectile Motion on an inclined plane [on hold]

There are two parallel planes, each inclined to the horizontal at an angle $\alpha$. A particle is projected from a point, midway between the two planes, such that it grazes one of the planes and ...
1
vote
0answers
22 views

2 Nucleon Potential

I am looking at a 2 Nucleon potential of the form $$V(r)=V_0(r)[a+bI_1\cdot I_2]$$ Where a and b are constants. $I_1,I_2$ are isospins. $V_0(r)$ is of the square well form. My goal is to find an ...
1
vote
0answers
9 views

Cubic Gaussian Surface For Evaluating Electric Flux

i'm working through some problem sets about Gauss' law and all the examples I have come across so far require the use of a spherical gaussian surface for a point charge, so that it is possible to say ...
0
votes
1answer
21 views

Calculating the distance between Detector and Double Slit

I have a little problem that is kind of confusing me at the moment. The following task: Light of the wavelength $\lambda = 500nm$ hits a double slit whose distance is $a = 30\mu m$. Each is $a = ...
0
votes
1answer
68 views

Relative motion setting course of closest approach

Let $r_{P/Q}$ be the position vector of $\overrightarrow P$ relative to vector $\overrightarrow Q$ and $v_{P/Q}$ the velocity vector of $\overrightarrow P$ relative to $\overrightarrow Q$. Suppose ...
0
votes
1answer
29 views

Finding the odd parity bound state wave function for a particle in one dimension

Let a particle of mass $m$ and energy $E$ be moving on the $x$-axis in a potential $V(x)$ given by $$V(x)=\left\{\begin{matrix} -V_{0}, & -a<x<a\\ 0, & otherwise \end{matrix}\right.$$ ...
0
votes
2answers
29 views

Velocity required for orbit of satellite

I am very confused about orbital velocity for satellite launched from earth. It is states that: $$ v=\sqrt{\frac{GM}{r}} $$ Some says that it is equal to 8000 m/s and some say 3.1 km/s. Please remove ...
1
vote
1answer
34 views

Temperature in a Voltaic Cell

The potential difference across a voltaic cell varies with temperature. But my question is whether the voltage increases or decreases as temperature rises. According to the Nernst equation, the two ...
-3
votes
0answers
33 views

Gravity problem [on hold]

If :Two objects of the same mass are situated in diametrically opposite points of Earth’s surface to achieve the time to reach the Moon. These objects belong to the centers of the mentioned celestial ...
0
votes
1answer
34 views

Normalizing the sum of wavefunctions and calculating probabilty - understanding concepts

A state of a particle bounded by infinite potential walls at x=0 and x=L is described by a wave function $\psi = a\phi_1 + b\phi_2 $ where $\phi_i$ are the stationary states. So let's say we want to ...
0
votes
0answers
32 views

How does the angle and mass affect the efficiency of a cart moving up a ramp?

A cart is pushed from a spring up a inclined plane. Therefore efficiency = (Gravitational Potential Energy + Work done by friction)/Elastic potential energy So what would increasing the angle do to ...
-1
votes
0answers
19 views

Thermodynamics Assignment: Combustion [on hold]

Acetylene, Methane and Octane are burnt in air (75% Nitrogen, 25% Oxygen) and forms Carbon Dioxide, Carbon Monoxide, Nitrogen and Water This is the unbalanced equation: C2H2 + CH4 + C8H18 + O2 + N2 ...
0
votes
0answers
34 views

Particle in a 2D box degeneracy [on hold]

I'm doing revision for my quantum test next week and my university, irritatingly, doesn't provide mark schemes to past questions. I feel like I've done most of this one right, but the end has thrown ...
1
vote
1answer
37 views

Does the energy-time uncertainty principle require energy levels to have finite width?

The uncertainty principle also has the form: $\Delta$$E$$\Delta$$t>h/2\pi$ Now this should mean that the thickness of the lines we draw in the energy level diagrams to show energy change undergone ...
0
votes
0answers
12 views

Question regarding to the uncertainty of an experiment [on hold]

recently I have done an experiment to find g. After some calculation, I have found the percentage uncertainty for 1/2g to be ±6.5%. Does that mean the percentage uncertainty for g is also this value? ...
-1
votes
2answers
32 views

Rubber bands and Hooke's law [on hold]

Why does increasing the width of a rubber band increase its elastic constant($k$)? And why are the two variables directly proportional? Explain it in terms of the structure of the band, if that is ...
0
votes
1answer
58 views

Is it possible to work out the shortest time in which a body can travel a certain distance if all that is provided is the max a, max -a, v1, v2 and s?

Is it possible to calculate the shortest time it takes a body to travel a certain distance if the only information provided is its maximum acceleration, its maximum retardation and the distance it ...
0
votes
1answer
34 views

Change of variable in harmonic oscillator time independent Schrodinger equation

I was revising the harmonic oscillator for my intro to quantum course and realised I'd sort of accepted a change of variable result without actually being able to get to it. It says: The stationary ...
-3
votes
0answers
32 views

How to solve this torque problem [on hold]

The Answer to the Question is 0.15Kg Is there anything wrong with the question or is it just me. Please Help. I tried working backward but didn't work.
-3
votes
0answers
29 views

Charge by Induction [on hold]

For example, Initially, there are two metal sphere touching each other and the ball on the left has a charge of +5q, while the other is neutral. Then a rod with charge -3q is brought near the left ...
1
vote
1answer
27 views

Plane Polar coordinates for simple pendulum in moving lift(elevator) [on hold]

Can any one help me with the following. A simple pendulum is suspended from the ceiling of a lift. It is moving upward with acceleration $a$. The string of the effective length of the pendulum makes ...