Question

Given: The unit weight of water is 62.4 lb/ft³

            Find:    The unit weight of water in kN/m³. The density of water in slug/ft³ and kg/m³

Answer 1

= density = 62.4 lb/ft³

we know that : 1 lb = 4.45 N and 1 ft = 0.305 m

hence

= 62.4 (lb/ft³ ) (4.45 N/1 lb) (1 ft/0.305 m)³

= (62.4) (4.45) (1/0.305)³ N/m³

= 9.786 kN/m³

we know that : 1 slug = 32.174 lb

hence

= 62.4 (lb/ft³ ) (1 slug /32.174 lb)

= (62.4/32.174) Slug/ft³

= 1.94 Slug/ft³

we know that : 1 lb = 0.454 kg and 1 ft = 0.305 m

hence

= 62.4 (lb/ft³ ) (0.454 kg/1 lb) (1 ft/0.305 m)³

= (62.4) (0.454) (1/0.305)³ kg/m³

= 998.5 kg/m³