Answer Key: EV3 - Get Moving Unit level

Submitted by Randy Steele on 21 November, 2013 - 07:40

Answer Key: Unit Quiz

  1. Rotations – the number of full rotation of the motors
    Degrees – the number of degrees of rotation of the motors (1 full rotation equals 360 degrees)
    Seconds – the number of seconds the motors will run
    On – turn motors on and immediately run the next block in the program
    Off - immedaitely turn off the motors
  2. Brake – stops motors abruptly
    Coast – removes power from the motor and allows them to stop slowly come to a stop
  3. 15/500 = 50/? 
    50/15 = 3.333
    ? = 500 x 3.333 = 1,666.7 degrees
  4. Move Forward, full speed, for 1 rotation, then stop abruptly
  5. Move Backward, 75% power, 720 degrees (2 rotations), then coast to a stop
  6. Move Forward, 50% power, for 2 second and then stop abruptly
  7. Tribot would not move
  8. A threshold is a cut-off value that divides a range of numbers into two groups: those above the threshold and those below.
  9. Some thresholds (like those for a color sensor) need to be calculated since they cannot be measured directly.  (i.e. if bright is 75 and dark is 25, the threshold, 50,  cannot be measured directly in Port View Mode, it must be calculated from the two values which can be measured).
  10. Since the threshold is 17 ((26+8)/2 = 17), the current reading of 16 is below the threshold and will be interpreted as dark.
  11. Gear Ratio = 8/24 = 1/3, this is an example of gearing down, since 1/3 < 1 .
  12. You want to gear up when you want more speed (at the expense of torque).  A dragster is an example of when you would want to gear up.
  13. You want to gear down when you want more torque (power).   Climbing a steep ramp or carrying a heavy load are examples of when you would want to gear down.
  14. Since the Wait-for-Light Block is waiting for bright (>50), then the floor must be dark.  Since the line is 10 above the threshold, then the dark floor must be 10 below the threshold, or 40. (Alternatively, 50 x 2 = 100; 100 – 60 = 40, so the floor must be 40).
  15. Raise the volume to 100% and change the Play Type parameter to '0' for Wait for Completion of sound before running next block (turning on load motors).
  16. The tribot will start moving when the light is turned on, run forward for 15 seconds, and then stop.  Ziffle needs to change the first Move Steering Block duration to ON.