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    Electric field on a surface

    Homework Statement A metallic surface is placed in an electrostatic field. Derive an expression for the electric field on the metal surface. Homework Equations \oint \underline{E} \cdot d\underline{A}=\dfrac{q_{enc}}{\epsilon_0} The Attempt at a Solution My initial thought was to set up a...
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    Uniform magnetic field and electric field

    Homework Statement How would you find the period of a charged particle in an uniform electric and magnetic field? The charged particle has velocity that is perpendicular to the magnetic and electric field (which are directed in the x-axis). Homework Equations F=q(E+vxB) The Attempt...
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    First Law of Thermodynamics

    Homework Statement 5 litres of an ideal gas which is initially at 300K and 10atm, and is expanded to a final pressure of 1atm. Find work done, change in internal energy, heat absorbed and change in enthalpy of the system if the process is isothermal and reversible. Homework Equations...
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    Relativity, time difference from two planets

    Homework Statement Two planets A and B have relative velocities 0.7c. They can observe the birth of two stars, C and D. According to planet A, star D was born 10 years before star C was born. According to planet B, star C was born 20 lightyears farther than star D. What is the time...
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    Lorentz transformation question, please help

    Homework Statement Two spaceships A and B are launched from a point X, in opposite directions. At time t=15 minutes, spaceship A crashes. The velocity of the spaceships relative to X is 1.3x10⁸m/s. How far did the collision happen from B, as observed by astronauts on the spaceship...
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    How to answer question on momentum?

    Homework Statement I am not sure wether I should take the value of velocity as a negative or positive in momentum questions. A cart (cart 1) of mass 5kg is travelling to the right with a velocity of 5m/s and another cart (cart 2) of mass 5kg is travelling to the left with a velocity of 1m/s...
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    Total energy of an object.

    Homework Statement If a question asks to calculate total energy of an object that does have a horizontal velocity (constant, air resistance ignored), and it is at it's highest point so it's vertical velocity is zero. I need to know how you'd calculate the total energy of this object...
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    First Law of Thermodynamics

    Homework Statement I am looking into the first law of thermodynamics. But I'm not sure with some parts. Homework Equations dU=Q-W What does it mean when U Q and W are negatives. Also solids with W=0 The Attempt at a Solution So the equation will change to -U=-Q+W Does it lose it's...
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    Wave question

    Homework Statement a) A microwave transmitter T and receiver R are placed side by side facing two sheets of material M (aluminium) and N (hardboard). A very small signal is registered by R; what can you deduce about the experimental set up? b) When M is moved towards N a series of maxia and...
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