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.
The weight of a piece of styrofoam depends on its size and density. On average, one cubic foot of styrofoam weighs about 1.5 pounds.
A standard 9-inch styrofoam plate typically weighs around 5 grams.
A single styrofoam tray typically weighs around 20-30 grams, depending on its size and thickness.
The weight of a cardboard box can vary depending on the size and thickness of the box. On average, a small cardboard box may weigh around 0.2-0.5 pounds, while a larger box can weigh 1-2 pounds.
About 75 LBS when you weigh the bottom and cardboard incert together
A Styrofoam cup weighs about 4.4 grams.
The weight of a piece of styrofoam depends on its size and density. On average, one cubic foot of styrofoam weighs about 1.5 pounds.
A standard 9-inch styrofoam plate typically weighs around 5 grams.
A single styrofoam tray typically weighs around 20-30 grams, depending on its size and thickness.
The weight of a cardboard box can vary depending on the size and thickness of the box. On average, a small cardboard box may weigh around 0.2-0.5 pounds, while a larger box can weigh 1-2 pounds.
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
About 75 LBS when you weigh the bottom and cardboard incert together
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).
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.
Yes, sand is generally heavier than Styrofoam. Sand has a much higher density, meaning it is more compact and contains more mass in a given volume compared to Styrofoam, which is a lightweight material made from expanded polystyrene. Consequently, if you compare equal volumes of both materials, sand will weigh significantly more than Styrofoam.
The weight of a cardboard tube from a toilet paper roll typically ranges from 10 to 20 grams, depending on the brand and type of toilet paper.
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.