PHY100F - The Magic of Physics.

Homework set #1.

1. Bruiser McDonohough started life as a professional boxer. Unfortunately he was not very successful, and after being struck repeatedly in the face and forehead by his more skilled opponents he began to suffer brain damage. Would you expect that the brain damage occurred at the front or at the back of his brain? Explain.

2. While standing on the subway train you feel a force as the train speeds up. Does this force act towards the front or towards the back of the train? How about when the train slows down? Explain.

3. A stone falling from the roof of a single story building to the surface of the earth;

  • A) reaches its maximum speed quite soon after release and then falls at a constant speed thereafter.
  • B) speeds up as it falls, primarily because the closer the stone gets to the earth, the stronger the gravitational attraction.
  • C) speeds up because of the constant gravitational force acting on it.
  • D) falls because of the intrinsic tendency of all objects to fall toward the earth.
  • E) falls because of a combination of the force of gravity and the air pressure pushing it
  • Which answer(s) are correct?

    4. A book is at rest on a table top. Which of the following force(s) is(are) acting on the book?

    1. A downward force due to gravity. 2. The upward force by the table.
    3. A net downward force due to air pressure. 4. A net upward force due to air pressure.
  • A) 1 only
  • B) 1 and 2
  • C) 1, 2, and 3
  • D) 1, 2, and 4
  • E) none of these, since the book is at rest there are no forces acting on it.
  • two people pulling a block




    5. Two people, a large man and a teeny tiny boy, are pulling as hard as they can on two ropes attached to a crate as illustrated in the diagram to the right. Which of the indicated paths (A-E) would most likely correspond to the path of the crate as they pull it along? (You may assume that the man is much stronger than the teeny tiny boy).


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