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Robotics Worksheet: Ultrasonic Distance Sensor

Robotics lesson 17: The distance sensor · Set 979 · 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.📡 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?
  2. 2.📡 A robot is 220 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)?
  3. 3.📡 What does an ultrasonic distance sensor send out? (a) water drops (b) sound too high to hear (c) bright light (d) radio music
  4. 4.📡 Which animal finds its way by echoes, like this sensor? (a) a bat (b) a goldfish (c) a cow (d) a snail
  5. 5.📡 A robot is 140 cm from a wall and drives straight at it at 10 cm per second. How far from the wall is it after 5 seconds (in cm)?
  6. 6.📡 A distance sensor sends a sound pulse and hears the echo 20 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  7. 7.📡 In these lessons, sound travels about how far in 1 millisecond? (a) 340 cm (b) 3 cm (c) 34 cm (d) 1 km
  8. 8.📡 Which object is hardest for an echo sensor to notice? (a) a flat wall (b) a wooden box (c) a soft foam cushion (d) a metal door
  9. 9.📡 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)?
  10. 10.📡 A robot is 130 cm from a wall and drives straight at it at 5 cm per second. How far from the wall is it after 20 seconds (in cm)?
  11. 11.📡 A robot is 150 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)?
  12. 12.📡 An object is 136 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  13. 13.📡 Why do we halve the echo’s total path? (a) the sensor is half (b) to make it smaller (c) it goes there and back (d) sound is slow
  14. 14.📡 A robot stops if an object is closer than 50 cm. Its distance sensor hears the echo after 4 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  15. 15.📡 An object is 238 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  16. 16.📡 A robot stops if an object is closer than 60 cm. Its distance sensor hears the echo after 2 ms (sound: about 34 cm per ms). Does the robot stop? (a) No (b) Yes
  17. 17.📡 A robot is 210 cm from a wall and drives straight at it at 15 cm per second. How far from the wall is it after 6 seconds (in cm)?
  18. 18.📡 A robot stops if an object is closer than 50 cm. Its distance sensor hears the echo after 6 ms (sound: about 34 cm per ms). Does the robot stop? (a) No (b) Yes
  19. 19.📡 A robot stops if an object is closer than 60 cm. Its distance sensor hears the echo after 8 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  20. 20.📡 A robot is 140 cm from a wall and drives straight at it at 5 cm per second. How far from the wall is it after 10 seconds (in cm)?
  21. 21.📡 A distance sensor sends a sound pulse and hears the echo 2 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  22. 22.📡 An object is 68 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  23. 23.📡 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)?
  24. 24.📡 An object is 153 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  25. 25.📡 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 1 second (in cm)?
  26. 26.📡 A distance sensor sends a sound pulse and hears the echo 1 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  27. 27.📡 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?
  28. 28.📡 A robot is 130 cm from a wall and drives straight at it at 15 cm per second. How far from the wall is it after 6 seconds (in cm)?
  29. 29.📡 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?
  30. 30.📡 A robot stops if an object is closer than 100 cm. Its distance sensor hears the echo after 2 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  31. 31.📡 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?
  32. 32.📡 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)?
  33. 33.📡 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?
  34. 34.📡 A distance sensor sends a sound pulse and hears the echo 17 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  35. 35.📡 A robot stops if an object is closer than 60 cm. Its distance sensor hears the echo after 3 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  36. 36.📡 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?
  37. 37.📡 A robot stops if an object is closer than 50 cm. Its distance sensor hears the echo after 1 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  38. 38.📡 A robot is 190 cm from a wall and drives straight at it at 10 cm per second. How far from the wall is it after 3 seconds (in cm)?
  39. 39.📡 A robot stops if an object is closer than 60 cm. Its distance sensor hears the echo after 4 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  40. 40.📡 A distance sensor sends a sound pulse and hears the echo 15 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?

Answer key

  1. 11
  2. 145
  3. sound too high to hear
  4. a bat
  5. 90
  6. 340
  7. 34 cm
  8. a soft foam cushion
  9. 204
  10. 30
  11. 110
  12. 8
  13. it goes there and back
  14. No
  15. 14
  16. Yes
  17. 120
  18. No
  19. No
  20. 90
  21. 34
  22. 4
  23. 238
  24. 9
  25. 250
  26. 17
  27. 15
  28. 40
  29. 2
  30. Yes
  31. 10
  32. 102
  33. 19
  34. 289
  35. Yes
  36. 17
  37. Yes
  38. 160
  39. No
  40. 255

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