Réponse :

Explications étape par étape :

a) 10 m/s = 10 x 60 m/min = 600 m/min = 600 x 60 m/h = 36000 m/h

   = 36 km/h

b) 18 km/h = 18000m/h = 18000/60 m/min = 300 m/min = 300/60 m/s

   = 5 m/s

c) 15 hm/s = 15 x 60 hm/min = 900 hm/min = 900 x 60 hm/h = 54000 hm/h

  = 5400 km/h

d) 9 dam/h = 90 m/h = 90/60 m/min = 1,5 m/min = 1,5/60 m/s = 0,025 m/s