Answer: Each wheel makes 437.5 revolutions in 20 mins
Explanation:
Circumference = 2πr
Given that the radius is 40 cm
Circumference = 2π(40) = 80π cm
Find the distance traveled in 20 mins
Speed = 66 km/h
1 hour = 66 km
Rewrite hour into min
60 min = 66 km
1 min = 66 ÷ 60 = 1.1 km
Rewrite km in cm
1.1 km = 1.1 x 10,000 cm = 110,000 cm
Find the number of revolutions in 20 mins:
1 revolution = 80π cm
Number of revolution = 110,000 ÷ 80π = 437.5