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  1. C

    Pendulum hanging from a roller coaster

    Ahh, that's right, I missed the tension created by Fg in part D. Thanks! I'm lost on the net force bit. The cart is at the very top of the track upside down and the only acceleration is centripetal. Since centripetal acceleration is always to the center of the orbit circle and the direction...
  2. C

    Heat Engine lifting a mass

    Homework Statement A heat engine operating between temperatures of 500 K and 300 K is used to lift a 10-kilogram mass vertically at a constant speed of 4 meters per second. (a) Determine the power that the engine must supply to lift the mass. (b) Determine the maximum possible efficiency...
  3. C

    Pendulum hanging from a roller coaster

    (d) I drew a vector diagram to help. So I've got a right triangle with hypotenuse 5.0 m/s^2 and a 30 degree angle. Sin 30 = x / 5.0 m/(s^2) = .5 (NOTE: Calculator set to degree mode) x (opposite side) = 2.5 m/(s^2) Cos 30 = y / 5.0 m/(s^2) = .866 y (adjacent side) = 4.33 m/(s^2) Now...
  4. C

    Pendulum hanging from a roller coaster

    Homework Statement In one roller coaster car, a small 0.10 kilogram ball is suspended from a safety bar by a short length of light, inextensible string. The car is then accelerated horizontally, goes up a 30 degree incline, goes down a 30 degree incline, and then goes around a vertical...
  5. C

    Calculate the magnitude and direction of the resultant force on the object.

    Almost. The magnitude is 2 and the direction is left. If the magnitude were -2 and the direction was to the left left, the motion would actually be to the right. That may be a bit confusing- does it make sense to you? Now that you know the mass, you can use F=ma to find the magnitude of the...
  6. C

    Calculate the magnitude and direction of the resultant force on the object.

    For part A, just call <----- negative and ------> positive. -9 N + 7 N = -2 N. I don't think part B is solvable without knowing the mass of the object.
  7. C

    Simple Harmonic Motion on an air track

    Thanks for the confirmation on the amplitude and period, diazona. I redid the calculation and discovered that I'd neglected to square the velocity to find KE- is this more in line with your calculations? Momentum final = mV 0.6 kg m/s = 1.5 kg * v V final = 0.4 m/s KE final = 1/2 (mass 1...
  8. C

    Simple Harmonic Motion on an air track

    Homework Statement A 0.20-kilogram mass is sliding on a horizontal, frictionless air track with a speed of 3.0 meters per second when it instantaneously hits and sticks to a 1.3-kilogram mass initially at rest on the track. The 1.3-kilogram mass is connected to one end of a massless spring...
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