A wheel of radius 1.4 m of car makes 70 revolution in 1 min. What is the speed of the car?
Answer & explanation
Correct answer: option 3
Radius of the wheel = 1.4 m
Time taken 70 revolution in 1 min
Distance covered in 1 revolution = circumference of wheel
circumference of wheel = 2πr
Speed = Distance/Time
1 min = (1/60) hr.
1 km = 1000 meter
According to the question:
Distance covered in 70 revolution = 2πr × 70
⇒ 2 × (22/7) × 1.4 × 70
⇒ 2 × (22/7) × (14/10) × 70 = 616 metre = 0.616 km
Now, Speed = 0.616/(1/60) = 36.96 km/hr