1. How many correct experiments do we need to disprove a theory? (A) one (B) two (C) three . (D) infinite 2. What's the dimension of light-year? (A) time (B) length (C) mass (D) velocity 3. A stone is thrown into the air at an angle above the horizontal and feels negligible air resistance. Which graph best depicts the stone's speed v as a function of time / while it is in the air? U C C (A) (B) (C) (D)