Robotics Worksheet: Ultrasonic Distance Sensor

Robotics lesson 17: The distance sensor · Set 12 · 40 questions

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.

1. 1.📡 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?
2. 2.📡 A robot stops if an object is closer than 30 cm. Its distance sensor hears the echo after 2 ms (sound: about 34 cm per ms). Does the robot stop? (a) Yes (b) No
3. 3.📡 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?
4. 4.📡 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) No (b) Yes
5. 5.📡 A robot stops if an object is closer than 100 cm. Its distance sensor hears the echo after 3 ms (sound: about 34 cm per ms). Does the robot stop? (a) No (b) Yes
6. 6.📡 A robot is 250 cm from a wall and drives straight at it at 20 cm per second. How far from the wall is it after 9 seconds (in cm)?
7. 7.📡 A robot is 150 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)?
8. 8.📡 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 5 seconds (in cm)?
9. 9.📡 Which animal finds its way by echoes, like this sensor? (a) a cow (b) a bat (c) a snail (d) a goldfish
10. 10.📡 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)?
11. 11.📡 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)?
12. 12.📡 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 12 seconds (in cm)?
13. 13.📡 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?
14. 14.📡 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 18 seconds (in cm)?
15. 15.📡 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)?
16. 16.📡 What does an ultrasonic distance sensor send out? (a) sound too high to hear (b) water drops (c) bright light (d) radio music
17. 17.📡 Which object is hardest for an echo sensor to notice? (a) a flat wall (b) a metal door (c) a wooden box (d) a soft foam cushion
18. 18.📡 A robot is 260 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)?
19. 19.📡 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 5 seconds (in cm)?
20. 20.📡 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)?
21. 21.📡 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?
22. 22.📡 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)?
23. 23.📡 A robot is 100 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)?
24. 24.📡 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)?
25. 25.📡 A robot is 120 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)?
26. 26.📡 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) Yes (b) No
27. 27.📡 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)?
28. 28.📡 A robot is 220 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)?
29. 29.📡 An object is 119 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 7 ms (sound: about 34 cm per ms). Does the robot stop? (a) No (b) Yes
31. 31.📡 A robot stops if an object is closer than 30 cm. Its distance sensor hears the echo after 3 ms (sound: about 34 cm per ms). Does the robot stop? (a) No (b) Yes
32. 32.📡 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)?
33. 33.📡 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 1 second (in cm)?
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 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)?
36. 36.📡 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?
37. 37.📡 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)?
38. 38.📡 Why do we halve the echo’s total path? (a) sound is slow (b) it goes there and back (c) the sensor is half (d) to make it smaller
39. 39.📡 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)?
40. 40.📡 A robot is 150 cm from a wall and drives straight at it at 5 cm per second. How far from the wall is it after 27 seconds (in cm)?

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