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    Kirchoff rule

    Homework Statement write two independent equations using kirchoff rule to describe the circuit. Homework Equations V=IR Emf = IR The Attempt at a Solution The answer is emf2 -I1R3-I2R2-I1R1 = 0 (ok i have questions here: why is it I1R1? shouldnt it be I4R1?) and...
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    One voltage, 3 resistors

    Homework Statement A circuit with one 5V and 3 resistors in parallel. What is the voltage across one of the resistors? Homework Equations V=IR The Attempt at a Solution 5/3 V?? or should i put R1 = 5V/I -R2-R3 V how do we get voltage across one of the resistors without...
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    Intergration Dipole

    Homework Statement We know the magnitude of the electric field at a location on the x axis and at a location on the y axis, if we are far from the dipole. (a) Find \DeltaV= V_p - V_a along a line perpendicular to the axis of a dipole. Do it two ways: from superposition of V due to the two...
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    2 Protons

    Homework Statement He2+ 2 protons and 2 neutrons Homework Equations E = Kq/r^2 The Attempt at a Solution to get q do square the charges of the proton? or do I multipy it by 2
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    Unwinding Cylinder-Dynamics

    Unwinding Cylinder--Dynamics Homework Statement A cylinder with a moment of inertia I (about its axis of symmetry), mass m, and radius r has a massless string wrapped around it which is tied to the ceiling (Intro 1 figure) . At time t=0 the cylinder is released from rest at height h...
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    Moving two blocks connected by a spring

    Homework Statement m_1, v_1f m_2, v_2f m_2 = m_1 = m Homework Equations KE = .5mv^2 W = F*d spring: F= -kx pot energy = PE = -.5kx^2 The Attempt at a Solution A) K + U = .5m(v_1f)^2 + .5m(v_2f)^2 - .5kx^2 .5(.1kg)(v_1f)^2 + .5(.1kg)(v_2f)^2 -.5(100N/m)(.02m)^2 B) ...
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    The Rotational Kinetic Energy of the Earth

    Homework Statement The Earth can be approximated as a sphere of uniform density, rotating on its axis once a day. The mass of the Earth is 5.97×10^24 kg, the radius of the Earth is 6.38×10^6 m, and the period of rotation for the Earth is 24.0 hrs. What is the moment of inertia of the...
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    Spinning situation

    Homework Statement Suppose you are standing on the center of a merry-go-round that is at rest. You are holding a spinning bicycle wheel over your head so that its rotation axis is pointing upward. The wheel is rotating counterclockwise when observed from above. For this problem, neglect...
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    Colliding Balls

    Homework Statement There are two balls travelling and they collide. How do there momentum change. What is the impulse done to ball B by ball A. Homework Equations delta momentum = 0 impulse = ? The Attempt at a Solution the first part i think its C becuz A is moving up...
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    An Exciting Encounter

    Homework Statement its asking me if if it is easier to use the mass units Homework Equations PART A The Attempt at a Solution its it easier to to use numbers given becuz when add the numbers (3.9) / ( 1 - 16 / (16+133) ) = 4.3 = kinetic energy needed for O ionize C 4.3 > 4...
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    Two worlds spinning

    Homework Statement There are two balls with masses m_a and m_b connected by a string. m_b is moving at a velocity v upwards (perpendicular to the string) and it asks for the Tension (T) in the string. Homework Equations a=(v^2)/R delta Energy of system = 0 T = m((u^2)/r) u is...
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    Weird globe

    Homework Statement there is a block sliding down a big globe in Italy. Homework Equations uhh The Attempt at a Solution does the globe have its own gravity? i'm thinking its A and C.
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    Launching from Mars

    Homework Statement The Radius of Mars is R_m its mass is m The radius of Mars (from the center to just above the atmosphere) is R_m and its mass is m. An object is launched from just above the atmosphere of mars. A) what is the object's initial velocity if its final velocity is V_f Homework...
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    Power dissipation

    Homework Statement Homework Equations P=F*V The Attempt at a Solution why isn't it P = Cd(A^2)(v^2) * (v) i dont see what i could do
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    Two blocks of power (2)

    Homework Statement the force is given as F the distance pushed is given as D Homework Equations W= F*d F=ma KE = 1/2 mv^2 The Attempt at a Solution the blocks have the same kinetic energy
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    Two blocks of power

    Homework Statement the force is given as F the distance pushed is given as D Homework Equations W= F*d F=ma KE = 1/2 mv^2 The Attempt at a Solution the blocks have the same kinetic energy
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    Conical pedulum

    HELP ME i tried spliting the forces of the tension of the string but I don't know how exactly
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