The wheel of a cart is making 5 revolutions per second. If the diameter of the wheel is 84 cm, find its speed in km/hr. Give your answer correct to the nearest km.
Radius =842=42 cm
Distance covered in one revolution = circumference of the wheel =2πr=2×227×42=264 cm
Distance covered in 5 revolutions = 264×5=1320 cm in 1 second
Distance covered in 1 hour =1320×3600=4752000 cm
= 47.52 km=48 km(approximately)
So, the speed = 48 km /hour