The wheel of a car has 210 cm diameter. How many revolutions per minute must the wheel make so that the speed of the car is kept at 120 km/h ?

326.42 245 303.03 289

303.03

120 km/h = 120 × \(\frac{5 }{18}\) m/sec = \(\frac{100 }{3}\) m/sec  Number of revolution = \(\frac{Speed × 60  }{ π × Diameter}\) = \(\frac{100 × 60 × 7 }{3× 22 × 2.1}\) = 303.03