Recent content by mjolnir80

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    Calculate Mass of Eri B & C: Solar Mass Ratio

    thanks for the help i used P^2/a^3 = 4 pi^2/ MG to get the mass
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    Calculate Mass of Eri B & C: Solar Mass Ratio

    ok so i got the reduced mass now i know that the formula for reduced mass is m1 + m2 / m1m2 but i don't really know where to go from here what I am having trouble understanding is where the parallax and ratio of distances comes in
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    Calculate Mass of Eri B & C: Solar Mass Ratio

    Homework Statement we are looking at two stars in the eridani system, eri B and eri C. the period of the system is 247.9 years. the system's measured trigonometric parallax is 0.201 arcseconds and the tru angular extent to the semimajor axis of the reduced mass is 6.89". the ratio of...
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    Astrophysics- unresolved binary star system

    Homework Statement Consider an unresolved binary star at a distance of 500pc consisting of an A1V dwarf and a K0III giant star. compute mb and mv and B-V for this object we know the mass, luminosty, radius, Mbol , Mv, Te , and B-V for each individual star. Homework Equations...
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    News No military option against the Iranian nuclear program

    sorry but how do you know they have antisemitic media, classic-style antisemitic cartoons? and only the ahmadinejad denies it not the government
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    Protons delivered per second in a proton beam

    Homework Statement a 5.0 mm-diameter proton beam carries a total current of 1.5mA. the current density in the proton beam, which increases with distance from the center, is given by j=j(edge)(r/R), where R is the radius of the beam and j(edge) is the current density at the edge. a) how many...
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    Calculating Electric Potential for a Wire with Linear Charge Density?

    Homework Statement the wire in the image below has a linear charge density \lambda . what is the electric potential at the center of the semicircle? http://img18.imageshack.us/img18/5139/physicsproblem.jpg Homework Equations The Attempt at a Solution i know that the potential from the semi...
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    Spinning rod dropping on a pivot

    Homework Statement a long, thin rod of mass M and length L is standing stright up on a table. its lower end rotates on a frictionless pivot. a very slight push causes the rod to fall over. as it hits the table, what are (a) the angular velocity and (b) the speed of the tip of the rod...
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    Hollow sphere rolling up a ramp

    v=\omegar right? but we don't have the radius of the sphere or do we....?
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    Hollow sphere rolling up a ramp

    Homework Statement a hollow sphere is rolling long a horizontal floor at 5 m/s when it comes to a 30 degree incline. how far up the incline does it roll before reversing direction?Homework Equations The Attempt at a Solution it seems like conservation of energy would work best for this problem...
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    Inelastic collision of a projectile with a pendulum

    im having problems dealing with the angle of the pendulum as it spins if we have the y-axis in the direction of centrifugal force the sum of the forces would be: ma = 400N - mgCos(angle) could i consider the ball when its at a 90 degree angle to get rid of that thing and at what point in...
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    Inelastic collision of a projectile with a pendulum

    Homework Statement a 20 kg wood ball hangs from a 2.0 m long wire. the maximum tension the wire can withstand without breaking is 400 n. a 1.0 kg projectile traveling horizontally hit and embeds itself in a the wood ball. what is the largest speed this projectile can have without causing the...
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    Ball rolling in a bowl problem

    Homework Statement a small ball slides , with constant speed (a\theta tangential acceleration = 0) , around a horizontal circle at height h inside a firctionless, hemispherical bowl of radius R. derive a formula for the balls angular velocity \omega in terms of the radius of the radius of the...
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    Rocket attatched to a spring problem

    Homework Statement a 10.2 kg weather rocket generates a thrust of 200N. the rocket ,pointing upwards, is clamped to the top of a vertical spring, whose spring constant is 500N/m and is anchored to the ground a)initially before the engine is ignited the sits at rest on top of the srping. how...
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