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Robotics Worksheet: Ultrasonic Distance Sensor

Robotics lesson 17: The distance sensor · Set 101 · 40 questions
TalentJR

Robot tip (Half the echo path): Distance (cm) = 17 × echo time (ms), because 34 cm per ms ÷ 2 for there and back. Echo time (ms) = distance × 2 ÷ 34. Distance after driving = distance now − speed × time.

NameDateTime takenScore ___ / 40
  1. 1.📡 Why do we halve the echo’s total path? (a) the sensor is half (b) it goes there and back (c) sound is slow (d) to make it smaller
  2. 2.📡 A robot stops if an object is closer than 30 cm. Its distance sensor hears the echo after 7 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  3. 3.📡 What does an ultrasonic distance sensor send out? (a) bright light (b) sound too high to hear (c) water drops (d) radio music
  4. 4.📡 A distance sensor sends a sound pulse and hears the echo 7 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  5. 5.📡 A distance sensor sends a sound pulse and hears the echo 9 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  6. 6.📡 A robot is 110 cm from a wall and drives straight at it at 15 cm per second. How far from the wall is it after 2 seconds (in cm)?
  7. 7.📡 A distance sensor sends a sound pulse and hears the echo 12 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  8. 8.📡 A distance sensor sends a sound pulse and hears the echo 6 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  9. 9.📡 A robot stops if an object is closer than 100 cm. Its distance sensor hears the echo after 5 ms (sound: about 34 cm per ms). Does the robot stop? (a) No (b) Yes
  10. 10.📡 An object is 170 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  11. 11.📡 A distance sensor sends a sound pulse and hears the echo 14 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  12. 12.📡 An object is 85 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  13. 13.📡 A robot stops if an object is closer than 60 cm. Its distance sensor hears the echo after 6 ms (sound: about 34 cm per ms). Does the robot stop? (a) No (b) Yes
  14. 14.📡 Which object is hardest for an echo sensor to notice? (a) a wooden box (b) a metal door (c) a soft foam cushion (d) a flat wall
  15. 15.📡 A robot is 220 cm from a wall and drives straight at it at 5 cm per second. How far from the wall is it after 8 seconds (in cm)?
  16. 16.📡 A robot is 230 cm from a wall and drives straight at it at 20 cm per second. How far from the wall is it after 1 second (in cm)?
  17. 17.📡 A robot stops if an object is closer than 30 cm. Its distance sensor hears the echo after 5 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  18. 18.📡 In these lessons, sound travels about how far in 1 millisecond? (a) 1 km (b) 34 cm (c) 340 cm (d) 3 cm
  19. 19.📡 An object is 34 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  20. 20.📡 An object is 221 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  21. 21.📡 A distance sensor sends a sound pulse and hears the echo 5 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  22. 22.📡 An object is 289 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  23. 23.📡 A robot is 130 cm from a wall and drives straight at it at 10 cm per second. How far from the wall is it after 6 seconds (in cm)?
  24. 24.📡 A robot stops if an object is closer than 30 cm. Its distance sensor hears the echo after 8 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  25. 25.📡 A robot is 190 cm from a wall and drives straight at it at 20 cm per second. How far from the wall is it after 5 seconds (in cm)?
  26. 26.📡 An object is 255 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  27. 27.📡 A distance sensor sends a sound pulse and hears the echo 10 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  28. 28.📡 An object is 187 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  29. 29.📡 A robot stops if an object is closer than 50 cm. Its distance sensor hears the echo after 5 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  30. 30.📡 A robot is 270 cm from a wall and drives straight at it at 20 cm per second. How far from the wall is it after 6 seconds (in cm)?
  31. 31.📡 A robot stops if an object is closer than 30 cm. Its distance sensor hears the echo after 1 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  32. 32.📡 A robot is 170 cm from a wall and drives straight at it at 15 cm per second. How far from the wall is it after 3 seconds (in cm)?
  33. 33.📡 A robot is 150 cm from a wall and drives straight at it at 10 cm per second. How far from the wall is it after 1 second (in cm)?
  34. 34.📡 Which animal finds its way by echoes, like this sensor? (a) a goldfish (b) a snail (c) a cow (d) a bat
  35. 35.📡 A robot is 100 cm from a wall and drives straight at it at 20 cm per second. How far from the wall is it after 2 seconds (in cm)?
  36. 36.📡 A robot is 180 cm from a wall and drives straight at it at 10 cm per second. How far from the wall is it after 15 seconds (in cm)?
  37. 37.📡 An object is 323 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  38. 38.📡 A distance sensor sends a sound pulse and hears the echo 19 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  39. 39.📡 A robot is 120 cm from a wall and drives straight at it at 15 cm per second. How far from the wall is it after 5 seconds (in cm)?
  40. 40.📡 A distance sensor sends a sound pulse and hears the echo 16 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?

Answer key

  1. it goes there and back
  2. No
  3. sound too high to hear
  4. 119
  5. 153
  6. 80
  7. 204
  8. 102
  9. Yes
  10. 10
  11. 238
  12. 5
  13. No
  14. a soft foam cushion
  15. 180
  16. 210
  17. No
  18. 34 cm
  19. 2
  20. 13
  21. 85
  22. 17
  23. 70
  24. No
  25. 90
  26. 15
  27. 170
  28. 11
  29. No
  30. 150
  31. Yes
  32. 125
  33. 140
  34. a bat
  35. 60
  36. 30
  37. 19
  38. 323
  39. 45
  40. 272

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