You need more information.
5 inch cube? Sphere? 5" thick of unspecified dimensions?
What is the density of the Styrofoam? What is the thickness and density of the cardboard? (weight per square inch?).
If you are creating something new, and wish to find a weight per square foot, per example, then you can probably get the required information on the WWW, or from your vendor.
About 75 LBS when you weigh the bottom and cardboard incert together
Use some standard of cardboard wt. per square ft, as a box has six sides, you have (length x width + length x height + width x height) x 2 x lb/ sq ft or if in metric kg/ sq m. Get net weight by subtracting cardboard wt from box wt. One standard cardboard box wt. in US is 0.13 kg/ sq m. This number will vary in US and, may be quite different in other countries.
how much is styrofoam unit weight?
Yes, metal is very much stronger than Styrofoam. Note, Styrofoam is a brand trade mark, forextruded polystyrene foam, much used as an insulator and packaging material.
The answer depends on how big a cube.
About 75 LBS when you weigh the bottom and cardboard incert together
A Styrofoam cup weighs about 4.4 grams.
Cardboard comes in different weights, depending on thickness, whether it is corrogated (i.e. with spaces), pressed, etc. So, the answer would depend first on the type and weight of the cardboard. Regardless of type of cardboard or the weight of the type, I would guess it would weigh far less than the CD and CD case together. I would further guess it would weigh about or less than the plastic CD case without the CD, with both CD and and extra cardboard piece being the same dimensions (height+width) and if the cardboard was thin. Lifes
That can vary a lot, depending on the thickness of the cardboard, as well as its consistency (it may be more or less densely packed).
Use some standard of cardboard wt. per square ft, as a box has six sides, you have (length x width + length x height + width x height) x 2 x lb/ sq ft or if in metric kg/ sq m. Get net weight by subtracting cardboard wt from box wt. One standard cardboard box wt. in US is 0.13 kg/ sq m. This number will vary in US and, may be quite different in other countries.
Not enough information to answer.... There is no 'standard' weight for cardboard. A box with walls of 4mm thickness will weigh less than the same size box, with walls of 6mm thickness.
how much is styrofoam unit weight?
12.6 kg
150
You can buy styrofoam and shave it into the shape of a lighthouse then paint it...or you can bye cardboard cut the shape of a lighthouse which is easier to paint then put detail with sharpie. much easier to carry if you build on a poster board
There is a right and a left radiator, together they weigh about 4 kg.
Yes, metal is very much stronger than Styrofoam. Note, Styrofoam is a brand trade mark, forextruded polystyrene foam, much used as an insulator and packaging material.