# Mass - 8th grade (13y) - math problems

Mass is a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a force is applied. An object's mass also determines the strength of its gravitational attraction to other bodies. The basic SI unit of mass is the kilogram (kg). Other are gram, tonne, milligram, etc.

#### Number of problems found: 216

• Mass
The thickness of a metallic tube is 1cm and its outer radius is 11cm. Find the mass of such 1m long tube, if the density of the metal is 7.5g per cubic cm.
• Carbon dioxide
Calculate how many grams of oxygen are in 50 g of carbon dioxide CO2. Relative atomic mass of oxygen is 16 and of carbon is 12.
• Density - simple example
Material of density of 532 kg/m3 occupies a container volume of 79 cm3. What is its mass?
• Air mass
What is the weight of the air in a classroom with dimensions 10 m × 10 m × 2.7 m ? The air density is 1.293 kg/m3.
• Cuboid 5
Calculate the mass of the cuboid with dimensions of 12 cm; 0.8 dm and 100 mm made from spruce wood (density = 550 kg/m3).
• Barrel of oil
Barrel of oil weighs 283 kg. When it mold 26% oil, weighed 216 kg. What is the mass of the empty barrel?
• Metal tube
Calculate the metal tube mass 8dm long with the outer radius 5cm and the inner radius 4.5cm and 1cm3 of this metal is 9.5g.
• Heating plant
Workers dump imported coke at heating plant. On the first day used half of the amount, the second day three quarters the rest and on the third day left 120 tons. How much coke they dump at heating plant?
• Cacao
Cacao contains 34% filling. How many grams of filling are in 130 g cacao.
• Gold horseshoe
Calculate the volume of a gold horseshoe that weighs 750g.
• Bracelet
The silver bracelet weighs 62g and contains 59g of silver. What is the purity of the bracelet?
• Butter fat
A quarter of kg butter contains 82% fat. How many grams of fat are in four cubes of butter?
• Gold coin
Gold coin contains 964 promile pure gold, which is 7.16 g. What is the weight of coin in grams?
• Weights
Marry and John together weighing 49 kg. Their weights are in ratio 1:6. Determine their weights.
• Mixture
How many percentages mixtures do we get by adding 23ml of matter to 89ml of water?
• Fe vs. H2O
The volume of what the body of the same weight is greater - iron or water?
• Weightlifter
Weightlifter lifted 75% of its weight. Determine how much weight lifted when he weighs 132 kg.
• Syringe and patient
In 1 ampoule of 2 ml is 15 mg of Dipidol. The patient should receive 10 mg. How much ml do I draw into the syringe?
• Meat loses
Meat loses 18% of its weight by smoking. How much raw meat butcher used to manufacture 35 kilos of smoked?
• Water percent
A 15 g sample of the substance contains 70% water. After drying, the weight was reduced to 9 g. What percentage of water is now in the sample?

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