Answer:
10
Explanation:
The speed of the chain is the same for both sprockets.
vᵢ = vₒ
ωᵢ rᵢ = ωₒ rₒ
The sprockets have the same pitch, so the radius is proportional to the number of teeth. So we can say:
ωᵢ nᵢ = ωₒ nₒ
Plugging in values:
(60 rpm) (40) = (240 rpm) nₒ
nₒ = 10
The output sprocket has 10 teeth. This makes sense, if the output sprocket is 4 times smaller, it will turn 4 times faster than the input sprocket.
