Mechanics II (pt 2)

  1. Every body in the universe _______ every other body with a mutually attracting force. For two bodies, this force is ______ proportional to the product of their masses and ______ proportional to the square of the distance separating them. State the formula
    • attracts
    • directly
    • inversely
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  2. The greater m1 and m2 is the _____ the force between them. The greater the distance of separation r, the ______ the force of attraction (for planets, this would be the distance between their ______)
    • greater
    • weaker
    • centers
  3. For a satellite orbit around a planet, the object is the _______. Net force on the satellite is the centripetal force and is due to _______ force 
    State the formulas for:
    Net force
    • satellite
    • gravitational force
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  5. Define torque
    It is the rotational equivalent of ______. It is the cause of changes in ______ motion and is analogous to _____.
    • Torque: T, is the tendency of a force to rotate an object about some axis
    • force
    • rotational
    • force
  6. Translational motion is to force as Rotational motion is to ______
  7. The applied force can act at an angle Φ with respect to the position vector, r.
    What is the formula for:
    Force when it is parallel vs perpendicular to the radial line. 
    Torque (state the units)
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  8. The ability of a force to cause a rotation depends on which 3 factors?
    • 1) The magnitude F of the force
    • 2) The distance r from the pivot (the axis about which the object can rotate) to the point at which the force is applied
    • 3) The angle Φ at which the force is applied
  9. The angle Φ is measured from the _______ line (define) to the direction of the _______
    • radial line: the line starting at the pivot and extending through the point at which the force is applied
    • force
  10. Torque is defined only when a _______ axis is specified, from which the distance r is determined. Define the moment arm and state the formula for both moment arm and how it can be incorporated to find torque
    • reference axis
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  12. Using the right rule, if the turning tendency of the force is counterclockwise, the torque will be ______. If the turning tendency is clockwise the torque will be _______.
    • positive
    • negative
  13. Torque depends on the force and where it is applied. Label the diagram by stating how much force will be applied
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  15. Since position r and torque T are vectors and magnitude of torque is T = _______. How do we define the T (cross product)
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  16. Given any two vectors, the vector product is a third vector: 
    What is the magnitude of the vector:
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  17. Review slide 63-64
  18. Two right hand rules to determine the direction of cross product
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  19. What does a rigid object in equilibrium mean for its net external force and external torque
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  20. For each of the following scenarios state whether the particle is at equilibrium:
    1) Net force on a particle is zero
    2) Both the net force and the net torque are zero
    3)The net force is still zero, but the net torque is not zero
    • 1) The particle is in static equilibrium
    • 2) The block is in static equilibrium
    • 3) The block is not in equilibrium
  21. Problem solving strategy: Rigid object in Equilibrium (5-story)
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  22. The net torque on an object in static equilibrium is zero when calculated about any _____ ______
    pivot point
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    *assume frictionless because "smooth"
  24. An extended object has a base of support on which it rests when in ______ _______. If you tilt the object, one edge of the base of support becomes a ______ ______
    • static equilibrium
    • pivot point
  25. For an object to balance, its center of gravity must reside over its base of support. That way gravity does not exert a ______. Label the diagram 
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    • torque 
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  26. Why cant you stand on tiptoes if your toes are against a wall?
    Center of gravity has to be over toes (the base of support) to balance. That requires shifting your body slightly forward. But you can't shift your body forward if your toes are against the wall
  27. When is the critical angle θc reached?
    What is the formula?
    What general rule does this lead to as it pertains to improving stability?
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  29. Review slide 76
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  32. Define the moment of inertia 
    Similar to the role mass plays in translational motion. What are two things the moment of inertia depends on
    What is the formula for moment of inertia (also state its units)
    • The moment of inertia: a measure of an object's resistance to change in its angular speed
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  33. Which will have the smaller moment of inertia and which will have the larger moment of inertia 
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  34. Given the object and axis with a picture, state the formula for Inertia 
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  35. Define ICM
    Incorporate this into a formula for net I
    • ICM: moment of inertia with rotation of axis through center of mass
    • I = ICM + MD2, moment of inertia with rotation of axis parallel to the axis through center of mass and a distance D from center of mass
  36. State the rotational dynamics equivalent for these: 
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  37. Problem solving strategy: Rotational dynamics (6-story)
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  38. If the pulley turns without the rope slipping on it, then the rope's speed must exactly match which speed?
    If the pulley has an angular acceleration, the rope's acceleration must match the _______ ________ of the rim of the pulley? 
    *State both as a formulas after answering
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    • the speed of the rim of the pulley
    • vrope = vrim = ωR
    • tangential acceleration 
    • αrope = αt = αR
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Card Set
Mechanics II (pt 2)
Mechanics II (pt 2)