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Robotics Worksheet: Gear Ratio for Kids

Robotics lesson 14: Gear ratio sums · Set 22 · 40 questions
TalentJR

Robot tip (Teeth × turns): Teeth passing = driver teeth × driver turns. Driven turns = teeth passing ÷ driven teeth. Gear ratio = driven teeth ÷ driver teeth (a ratio of 3 means 3 times slower).

NameDateTime takenScore ___ / 40
  1. 1.🔢 Gear ratio = driven teeth ÷ … (a) number of gears (b) motor volts (c) driver teeth (d) wheel size
  2. 2.🔢 A gear ratio of 3 (driven ÷ driver) means the driven gear turns … (a) 3 times faster (b) 3 times louder (c) 3 times slower (d) 3 times bigger
  3. 3.⚙️ A motor makes 400 turns a minute with a 15-tooth gear on it. That gear drives a 75-tooth gear. How many turns a minute does the 75-tooth gear make?
  4. 4.⚙️ An 8-tooth driver gear turns a 24-tooth driven gear. The driver turns 3 times. How many times does the driven gear turn?
  5. 5.⚙️ A 10-tooth driver gear must make the driven gear turn 5 times slower. How many teeth must the driven gear have?
  6. 6.🔢 To climb a steep ramp, a robot needs a gear ratio that is … (a) zero (b) big (slow and strong) (c) never important (d) small (fast, weak)
  7. 7.⚙️ A 10-tooth driver gear turns a 50-tooth driven gear. The driver turns 30 times. How many times does the driven gear turn?
  8. 8.⚙️ A motor makes 100 turns a minute with a 15-tooth gear on it. That gear drives a 30-tooth gear. How many turns a minute does the 30-tooth gear make?
  9. 9.⚙️ A 32-tooth driver gear turns an 8-tooth driven gear. The driver turns 2 times. How many times does the driven gear turn?
  10. 10.⚙️ A motor makes 330 turns a minute with a 15-tooth gear on it. That gear drives a 45-tooth gear. How many turns a minute does the 45-tooth gear make?
  11. 11.⚙️ A 20-tooth driver gear turns a 40-tooth driven gear. The driver turns 6 times. How many times does the driven gear turn?
  12. 12.⚙️ A 10-tooth gear drives a 40-tooth gear. What is the gear ratio (driven teeth ÷ driver teeth)?
  13. 13.⚙️ A 12-tooth gear drives a 24-tooth gear. What is the gear ratio (driven teeth ÷ driver teeth)?
  14. 14.⚙️ A 12-tooth driver gear turns a 48-tooth driven gear. The driver turns 32 times. How many times does the driven gear turn?
  15. 15.⚙️ An 8-tooth driver gear must make the driven gear turn 2 times slower. How many teeth must the driven gear have?
  16. 16.⚙️ A 15-tooth driver gear turns a 30-tooth driven gear. The driven gear turns 9 times. How many times did the driver turn?
  17. 17.⚙️ A 20-tooth driver gear turns a 100-tooth driven gear. The driven gear turns 4 times. How many times did the driver turn?
  18. 18.⚙️ An 8-tooth driver gear must make the driven gear turn 5 times slower. How many teeth must the driven gear have?
  19. 19.⚙️ A 20-tooth gear drives a 40-tooth gear. What is the gear ratio (driven teeth ÷ driver teeth)?
  20. 20.⚙️ An 8-tooth driver gear turns a 40-tooth driven gear. The driven gear turns 5 times. How many times did the driver turn?
  21. 21.⚙️ A 40-tooth driver gear turns a 20-tooth driven gear. The driver turns 2 times. How many times does the driven gear turn?
  22. 22.⚙️ A 30-tooth driver gear turns a 10-tooth driven gear. The driver turns 6 times. How many times does the driven gear turn?
  23. 23.⚙️ An 8-tooth driver gear must make the driven gear turn 3 times slower. How many teeth must the driven gear have?
  24. 24.⚙️ A motor makes 240 turns a minute with an 8-tooth gear on it. That gear drives a 24-tooth gear. How many turns a minute does the 24-tooth gear make?
  25. 25.⚙️ A 75-tooth driver gear turns a 15-tooth driven gear. The driver turns 3 times. How many times does the driven gear turn?
  26. 26.⚙️ A motor makes 270 turns a minute with a 15-tooth gear on it. That gear drives a 45-tooth gear. How many turns a minute does the 45-tooth gear make?
  27. 27.⚙️ An 8-tooth driver gear turns a 40-tooth driven gear. The driver turns 35 times. How many times does the driven gear turn?
  28. 28.⚙️ A motor makes 80 turns a minute with a 15-tooth gear on it. That gear drives a 30-tooth gear. How many turns a minute does the 30-tooth gear make?
  29. 29.⚙️ An 8-tooth driver gear turns a 24-tooth driven gear. The driver turns 21 times. How many times does the driven gear turn?
  30. 30.⚙️ A 20-tooth driver gear must make the driven gear turn 2 times slower. How many teeth must the driven gear have?
  31. 31.⚙️ A 40-tooth driver gear turns a 20-tooth driven gear. The driver turns 4 times. How many times does the driven gear turn?
  32. 32.⚙️ A motor makes 350 turns a minute with a 12-tooth gear on it. That gear drives a 60-tooth gear. How many turns a minute does the 60-tooth gear make?
  33. 33.⚙️ A 15-tooth gear drives a 60-tooth gear. What is the gear ratio (driven teeth ÷ driver teeth)?
  34. 34.⚙️ A 10-tooth driver gear must make the driven gear turn 3 times slower. How many teeth must the driven gear have?
  35. 35.⚙️ A 15-tooth driver gear must make the driven gear turn 3 times slower. How many teeth must the driven gear have?
  36. 36.⚙️ A motor makes 480 turns a minute with a 12-tooth gear on it. That gear drives a 48-tooth gear. How many turns a minute does the 48-tooth gear make?
  37. 37.⚙️ A 12-tooth driver gear turns a 24-tooth driven gear. The driver turns 2 times. How many times does the driven gear turn?
  38. 38.⚙️ A 15-tooth driver gear turns a 45-tooth driven gear. The driver turns 9 times. How many times does the driven gear turn?
  39. 39.⚙️ A 20-tooth driver gear must make the driven gear turn 4 times slower. How many teeth must the driven gear have?
  40. 40.⚙️ A motor makes 250 turns a minute with an 8-tooth gear on it. That gear drives a 40-tooth gear. How many turns a minute does the 40-tooth gear make?

Answer key

  1. driver teeth
  2. 3 times slower
  3. 80
  4. 1
  5. 50
  6. big (slow and strong)
  7. 6
  8. 50
  9. 8
  10. 110
  11. 3
  12. 4
  13. 2
  14. 8
  15. 16
  16. 18
  17. 20
  18. 40
  19. 2
  20. 25
  21. 4
  22. 18
  23. 24
  24. 80
  25. 15
  26. 90
  27. 7
  28. 40
  29. 7
  30. 40
  31. 8
  32. 70
  33. 4
  34. 30
  35. 45
  36. 120
  37. 1
  38. 3
  39. 80
  40. 50

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