Correct Answer - Option 1 : 36.96 km/hr
Given:
Radius of the wheel = 1.4 m
Time taken 70 revolution in 1 min
Formula used:
Distance covered in 1 revolution = circumference of wheel
circumference of wheel = 2πr
Where, r = radius
Speed = Distance/Time
Concept used:
1 min = (1/60) hr.
1 km = 1000 meter
Calculation:
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
∴ The speed of the car is 36.96 km/hr.
