Express 15 m s^-1 in km h^-1 .

Express each of the following in m s ^-1 —

(a) 1 km h^-1

(b) 18 km min^-1

A train takes 3 h to travel from Agra to Delhi with a uniform speed of 65 km h^-1. Find the distance between the two cities.

A car travels first 30 km with a uniform speed of 60 km h^-1 and then next 30 km with a uniform speed of 40 km h ^-1.

Calculate —

(i) the total time of journey,

(ii) the average speed of the car.