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Robotics Worksheet: Ultrasonic Distance Sensor

Robotics lesson 17: The distance sensor · Set 987 · 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 340 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  2. 2.📡 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)?
  3. 3.📡 Which animal finds its way by echoes, like this sensor? (a) a bat (b) a cow (c) a goldfish (d) a snail
  4. 4.📡 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 22 seconds (in cm)?
  5. 5.📡 Why do we halve the echo’s total path? (a) to make it smaller (b) the sensor is half (c) it goes there and back (d) sound is slow
  6. 6.📡 A robot is 280 cm from a wall and drives straight at it at 5 cm per second. How far from the wall is it after 25 seconds (in cm)?
  7. 7.📡 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?
  8. 8.📡 In these lessons, sound travels about how far in 1 millisecond? (a) 1 km (b) 3 cm (c) 34 cm (d) 340 cm
  9. 9.📡 What does an ultrasonic distance sensor send out? (a) bright light (b) water drops (c) radio music (d) sound too high to hear
  10. 10.📡 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)?
  11. 11.📡 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?
  12. 12.📡 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?
  13. 13.📡 A distance sensor sends a sound pulse and hears the echo 4 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  14. 14.📡 Which object is hardest for an echo sensor to notice? (a) a metal door (b) a flat wall (c) a soft foam cushion (d) a wooden box
  15. 15.📡 A robot is 180 cm from a wall and drives straight at it at 15 cm per second. How far from the wall is it after 4 seconds (in cm)?
  16. 16.📡 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?
  17. 17.📡 A robot is 110 cm from a wall and drives straight at it at 5 cm per second. How far from the wall is it after 5 seconds (in cm)?
  18. 18.📡 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)?
  19. 19.📡 A robot is 290 cm from a wall and drives straight at it at 10 cm per second. How far from the wall is it after 12 seconds (in cm)?
  20. 20.📡 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 1 second (in cm)?
  21. 21.📡 An object is 306 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  22. 22.📡 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) No (b) Yes
  23. 23.📡 A robot is 100 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)?
  24. 24.📡 A robot stops if an object is closer than 50 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 stops if an object is closer than 100 cm. Its distance sensor hears the echo after 4 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  26. 26.📡 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?
  27. 27.📡 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) No (b) Yes
  28. 28.📡 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) Yes (b) No
  29. 29.📡 A robot stops if an object is closer than 60 cm. Its distance sensor hears the echo after 7 ms (sound: about 34 cm per ms). Does the robot stop? (a) No (b) Yes
  30. 30.📡 A distance sensor sends a sound pulse and hears the echo 8 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
  31. 31.📡 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?
  32. 32.📡 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 4 seconds (in cm)?
  33. 33.📡 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)?
  34. 34.📡 An object is 272 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
  35. 35.📡 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
  36. 36.📡 A robot is 120 cm from a wall and drives straight at it at 5 cm per second. How far from the wall is it after 4 seconds (in cm)?
  37. 37.📡 A robot stops if an object is closer than 60 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 stops if an object is closer than 100 cm. Its distance sensor hears the echo after 1 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  39. 39.📡 A robot stops if an object is closer than 100 cm. Its distance sensor hears the echo after 6 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
  40. 40.📡 An object is 17 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?

Answer key

  1. 20
  2. 255
  3. a bat
  4. 20
  5. it goes there and back
  6. 155
  7. 4
  8. 34 cm
  9. sound too high to hear
  10. 204
  11. 14
  12. 15
  13. 68
  14. a soft foam cushion
  15. 120
  16. 13
  17. 85
  18. 102
  19. 170
  20. 115
  21. 18
  22. No
  23. 90
  24. No
  25. Yes
  26. 11
  27. Yes
  28. No
  29. No
  30. 136
  31. 8
  32. 20
  33. 340
  34. 16
  35. No
  36. 100
  37. Yes
  38. Yes
  39. No
  40. 1

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