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Some physics questions

  1. Sep 6, 2005 #1
    The answers that i think are correct have ***** next to them. If anyone knows the right answers please share your thoughts. Thank you.

    1. A ball is thrown downward (not dropped) from the top of a tower. After being released, its downward acceleration will be
    greater than g.
    exactly g.
    less than g.
    none of the above *****

    2. A rock is thrown up at a 45° angle. Neglecting air resistance, the x-component of the rock's velocity is
    greatest just after the rock is thrown
    greatest at the top of the rock's flight
    greatest just before the rock hits the ground
    always the same *****

    3. Velocity measurements
    differ in defferent frames of reference. *****
    are the same in any Galilean reference frame.
    are always largest in the reference frame of the Earth.
    are always smallest in the reference frame of the Earth.

    4. Which of these laws is not one of Newton's laws?
    Action force equals reaction force
    F = ma
    All objects fall with equal acceleration *****
    Objects at rests stay at rest, etc.

    5. Inertia
    expresses the tendency of bodies to maintain their state of motion. *****
    is Newton's third law.
    none of the above

    6. If vector B is added to vector A, the resultant vector A+B has a magnitude A+B when A and B are
    perpendicular to each other
    oriented in the same direction *****
    oriented in opposite directions
    in any direction relative to each other

    Thank you.
  2. jcsd
  3. Sep 6, 2005 #2


    User Avatar
    Homework Helper

    Look at question 1 ... greater than, equal to, or less than
    Don't these 3 cover the entire number line?
    WHAT OTHER possibility could there be?
  4. Sep 6, 2005 #3
    LOL. I don't make up the questions. The teacher does.

    if anyone has any info, lmk. thanks.
  5. Sep 7, 2005 #4

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    You may wish to reconsider your answers to 1 and 4.

    1 can't be 'none of the above', as lightgrav has correctly pointed out.

    4 is a little unclear. Objects at 'rest' stay at rest only if they are not subjected to a force. The second choice could be thought of as a statement of Newton's Law of Universal Gravitation, although it is more general than that.

  6. Sep 7, 2005 #5
    For Question 1. Acceleration is only at a constant 9.8m/s2 in free fall only. So considering there is air resistance i guess that Acceleration has to be less than 9.8 m/s2 then. LMK
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