# Mass - 7th grade (12y) - 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: 167

• Excavator The excavator bucket capacity is 0.5 m3. Determine the mass of sand that the excavator picks up. The sand density is 1650 kg/m3.
• 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.
• Nine balls Imagine that you have exactly the same appearance nine balls of which one has a greater mass than the other. You have isosceles weights. Post a procedure as you would using a weights to discover heavier balls. How many measurements at least you have to do
• 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).
• Pound2kilos How many pounds make 1 kilograms?
• 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?
• Iron pole What is the mass of pole with the shape of a regular quadrilateral prism with a length of 1 m and a cross-sectional side length of a = 4.5 cm make from iron with density ρ = 7800 kg/m³?
• 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?
• Recipe A recipe requires 2 pounds of flour. If a chef wants to triple the recipe, how many ounces of flour will be needed?
• Gold horseshoe Calculate the volume of a gold horseshoe that weighs 750g.
• Potatoes Potatoes contain 78.6% starch. How many potatoes need to obtain 27 kg of starch?
• Wood Wood density is 0.6 g/cm3. How many kilograms weight 1 m3 of wood?
• Planet Earth What is the weight of the planet Earth, if its average density is ρ = 2.5 g/cm ^ 3?
• Weights Marry and John together weighing 49 kg. Their weights are in ratio 1:6. Determine their weights.
• Coal mine The monthly plan of 17,000 tons of coal exceeded the mine by 1/25. How many tonnes of coal have been harvested from the mine above plan?
• Bottles The weight of 17 bottles is 91.7 kg. What is the weight of 1 bottle?
• Mixture How many percentages mixtures do we get by adding 23ml of matter to 89ml of water?

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