Answer to Question #1397 in Mechanics | Relativity for Mike
A 4.9 kg rectangular air mattress is 2.7 m
long, 1.16 m wide, and 0.183 m thick.
What mass can it support in water before
Answer in units of kg.
The object seems to be sunk when all its volume is under the water surface. The volume of the matress is V = 2.7*1.16*0.183 = 0.573 m3. Fa = ρ*g*V ; Archimedes force should be equal to the weight of the mattres with water: ρ*g*V = mg+Mg m = ρV - M = 1000 kg/m3 * 0.573 - 4.9 = 568.1 kg