Question

converter a speed of 54 km/h into m/s

Answer 1

1 km = 1000 m
1hour = 3600sec

54 km/h = 54*1000/3600 = 54*5/18 = 15 m/s

Answer 2

1 k/h = 5/18 m/ second so 54 * 5/18=15 m/s