Recent content by envscigrl

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    How Do You Calculate the Density Ratio of the Moon to the Earth?

    problem: The mass of the Earth is 5.98E+24 kg and its radius is 6370 km. The radius of the moon is 1738 km. The acceleration due to gravity at the surface of the moon is 1.62 m/s2. What is the ratio of the average density of the moon to that of the earth? (no units) I am very confused as...
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    Calculate the distance from the center of the Earth

    Problem: Calculate the distance from the center of the Earth to a point below the surface where the acceleration due to gravity is 0.50g, where g is the acceleration due to gravity at the Earth's surface. I thougtt I could use g = GMe / R^2 solving for R. But this did not work. This...
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    What is the Escape Speed Formula and How Do I Use It to Solve Problems?

    Thank you very much that makes a lot of sense!
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    What is the Escape Speed Formula and How Do I Use It to Solve Problems?

    problem: Taking the potential energy to be zero at infinite separation, find the potential energy of a 118.0-kg object at the surface of the earth. (Use 6.37E+6 m for the Earth's radius.) I did this and got -7.374E09. It then asks Find the escape speed for a body projected from this...
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    Calculating Distance from Center of Earth to Point with 0.50g Acceleration

    Problem: Calculate the distance from the center of the Earth to a point below the surface where the acceleration due to gravity is 0.50g, where g is the acceleration due to gravity at the Earth's surface. I am really stuck on this. I tried using T^2 = 4pi^2 / GMe *r^3 but it didnt work it...
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    Too easy and wrong: consv of angular momentum

    I swear I must have tried that problem a milllion different times last night but I just couldn't get it. When I tried again I got the right answer (553.7). I wasnt converting the angular speed from the first answer back into rev/s. Thanks so much for your help!
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    Too easy and wrong: consv of angular momentum

    Here is my problem: A man stands at the center of a platform that rotates without friction with an angular speed of 1.60rev/s. His arms are outstretched, and he holds a heavy weight in each hand. The moment of inertia of the man, the extended weights, and the platform is 6.30 kg m2. When the...
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    PHysics PHysics Physics Physics Torque

    Here is my problem: A 2.50g particle moves in a circle of radius 3.00m. The magnitude of its angular momentum relative to the center of the circle depends on time according to L = (3.5 Nm)t. Find the magnitude of the torque acting on the particle. I know that: T = F L where T = torque F...
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    Philosophy: Should we eat meat?

    I am a vegetarian and have been for two years now. I eat fish and eggs and have recently started eating chicken again (not often, once every two weeks or so). I did this for protein resons because I am in college and on the go and don't often get enough protein from my current fav foods ( ie EZ...
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    Solid Ball Problem: Kinetic Energy Calculation

    Here is my last problem I am having problems with: A solid ball of mass 1.70kg and diameter 16.0cm is rotating about its diameter at 65.0rev/min. What is its kinetic energy ? Ok so KE for rotation is : 1/2*I *w^2 so I found I with m *r2 and then plugged everything...
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    Why Is Calculating the Moment of Inertia for a Wagon Wheel Complex?

    A wagon wheel 1.00m in diameter consists of a thin rim having a mass of 7.25kg and six spokes each having a mass of 1.30kg. Determine the moment of inertia of the wagon wheel for rotation about its axis. I thought that I could simply sum the masses (7 of them) and the multiply them by them...
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    Help! Moment of Inertia for Tangent Axis of Sphere

    Help! tangent axis Use the parallel-axis theorem to find the moment of inertia of a solid sphere of mass M=3.80kg and radius R=2.30m about an axis that is tangent to the sphere. I am being thrown off this problem because the axis is TANGENT to the sphere and not through the center. According...
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    How Do Volcanic Eruptions and CFCs Influence Global Warming?

    I am not sure about b and c but I know that a volcanic eruption would have the reverse effect of global warming because it emits sulfur which reacts with water vapor to form sulfur dioxide which then blocks the suns rays from reaching the Earth and thus cools the planet. Dont think though that...
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    What is the Velocity of the Center of Mass in a Proton-Carbon Collision?

    A proton of mass m undergoes a head-on elastic collision with a stationary carbon nucleus of mass 12×m. The initial velocity of the proton is 790 m/s in the positive x direction. Find the velocity of the center of mass of the system. I am really confused as to how to find the 'velocity of...
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    A car crashes into a concrete wall

    Here it is: A 2000-kg car traveling at 85.0 km/h crashes into a concrete wall that does not give at all. Estimate the time of the collision, assuming that the center of the car travels halfway to the wall with constant deceleration. (Use 5.75 m for the length of the car.) I know I need to...
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