A motor gear with 12 teeth drives a wheel gear with 48 teeth. What is the gear ratio?
A1:4
B4:1
C12:48
D60:1
Gear ratio = driven teeth / driving teeth = 48/12 = 4:1. The wheel gear turns 4 times slower than the motor gear but with 4 times the torque.
Question 2 True / False
If a gear ratio increases torque, it is expected to also increase speed.
TTrue
FFalse
Answer: False
Gears trade speed for torque. A higher gear ratio (more torque) means lower output speed. The relationship is inverse: torque × speed is approximately constant (equal to the input power).
Question 3 Short Answer
A bicycle's front gear has 44 teeth and the rear gear has 11 teeth. How many times does the rear wheel rotate for each pedal revolution?
Think about your answer, then reveal below.
Model answer: 4 times. The gear ratio is 44/11 = 4, so for every one turn of the pedals, the rear wheel turns 4 times. This is a high gear -- fast but requires more pedaling force.
The front gear (driving) has more teeth than the rear gear (driven), so the rear wheel spins faster than the pedals. Each pedal revolution turns the rear wheel 44/11 = 4 times. This high gear ratio favors speed over ease of pedaling.