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Sound, balloons, light, & pressure questions

  1. Dec 5, 2008 #1
    1. The problem statement, all variables and given/known data

    Question 1: A gram of radioactive material has a half life of x.

    2. Relevant equations

    Please not that this is a generally question and I am not actually solving for X.
    After x amount of time, how much will be left?

    3. The attempt at a solution
    I believe the answer is somewhere along the lines of: The half-life is the time required for half the atoms in the sample to decay.

    Question 2: When light reflects from a surface, there is a change in its?
    I am not exactly sure what the teacher is wanting for the answer. Any ideas?

    Question 3: Gas pressure inside an inflated, stretched balloon is actually____________.
    equal, less than, greater than

    Question 4: In a vacuum, a marshmallow becomes__________.
    My guess is that it becomes bigger.

    Question 5: When an alpha particle is ejected from the nucleus, the nucleus has less________. (Charge, mass, both, neither)
    My guess would be less charge because the alpha particle is two neutrons and two protons--which have charges.

    Question 6: What is the speed of a free falling object--if air resistance is absent--on the 3rd second?
    I am not sure of this question at all. Is there a formula for a problem like this?

    Please note that I am NOT trying to have someone do my homework for me. I would like explanations of why the answer is the answer. Thanks in advance!!

  2. jcsd
  3. Dec 5, 2008 #2


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