A waterbed mattress has the following dimensions: 210 cm X 160 cm X 27 cm. The density of water is 62.4lb/ft3. What is the weight of the bed in pounds?
If the mattress is placed on the floor (no bed frame), how much pressure does it exert on the floor in pounds per square inch?

Question

A waterbed mattress has the following dimensions: 210 cm X 160 cm X 27 cm. The density of water is 62.4lb/ft3. What is the weight of the bed in pounds?
 If the mattress is placed on the floor (no bed frame), how much pressure does it exert on the floor in pounds per square inch?

mathmate · Answer

If the answer is to be in psi, you'd be better off converting everything to the imperial system, namely for linear measurements, 1 ft=0.3048m (exactly), or 1 inch = 2.54 cm (exactly)
So the volume of the bed is V= (2.10/0.3048)*(1.60/0.3048)*(0.27)/0.3048) ft^3
62.4V gives the weight of the bed in pounds.
Distribute the total weight over the horizontal area of the bed (in sq.inches) to get the pressure in #/sq.in.

koikkara · Answer

similiar example : https://in.answers.yahoo.com/question/index?qid=20111007112021AArl1yg @kdancer03