Answers for Practice Test #1

  1. Motion diagram. On the first straight stretch there should be acceleration vectors pointing toward the top of page. On the curve there should be a acceleration vectors pointing to the inside of the curve. On the second straight stretch there should be acceleration vectors pointing to toward the right.
  2. (a) graphical addition of vectors => redraw the vectors (same length and direction) and add them either tip-to-tail or by completing the parallelogram.
    (b) resultant vector = 2i + 10j
    (c) magnitude is 10.2 and angle is 78.7o above positive x-axis.
  3. object ends up at 11. Make sure you can draw the graph correctly
  4. This is straight out of the student workbook from Friday's class
  5. BIG MONEY PROBLEM( remember that the problem solving strategy is where you will earn the majority of your points)
    xtotal=20m and total time = 10.2s (speed when you jump on the slide is 4.9m/s)
  6. (a) average velocity is -1.36 m/s
    (b)instantaneous velocity (slope of tangent line) is 5 m/s
    (extra) average acceleration is 3.02 m/s/s. HINT: you need to determine the instantaneous velocities (slope of tangent) at each of the two times in order to find the change in velocity.