Mass - practice for 14 year olds - page 7 of 22
Number of problems found: 435
- Confectionery 47211
They want to buy a mixture of candies for the confectionery, which consists of fruit candies at CZK 170/kg and chocolate candies at CZK 240/kg. The mixture should be 20 kg for 212 CZK/kg. How many fruit candies and how many chocolate candies must he buy? - Flatbed 47151
How many bricks do they have to lift on a 1.2 m high flatbed if I want to do the work 5.88kj and one brick weighs 5 kg? - Latent heat
How much heat is needed to take from 100 g of water at 20°C to cool to the ice at -18°C? Mass heat capacity c (ice) = 21kJ/kg/°C; c (water) = 4.19 KJ/kg/°C and the mass group heat of solidification of water is l = 334kJ/kg - Designated 44741
Cathedral height 110m, sphere weight 6000kg, dome diameter 43m, crane arm length 25m a) what was the diameter of this sphere? b) how much mechanical work had to be done to lift it to the designated place?
- Heat transfer
We placed a lead object weighing 0.4 kg and 250°C in 0.4 L water. What was the initial temperature of water t2 if the object's temperature and the water after reaching equilibrium was 35°C? We assume that the heat exchange occurred only between the lead o - Grams 44441
How many grams of 70% and 45% acid must be mixed to form 300 grams of 60% acid? - Calculate 44351
Calculate how many grams of iodine and ethanol are needed to prepare 200 grams of 6% iodine in ethanol solution. - Identical 44271
Ten identical trucks will take 240 tons of concrete to build the dam in 3 working days. How many tons of concrete will seven trucks take to make the dam in 5 days? - Movement 43831
The crane motor has a constant power of 9 kW. How long does it take to lift a body weighing 12 tons to a height of 9 m with constant movement?
- Rotation 43561
The boy is sitting on a two-arm swing, and his seat is 300 cm away from the center of rotation. Its weight is 48 kg. The girl is sitting at the other end of the swing, and her mass is 36 kg. How far from the center of rotation must the girl sit for them t - Substitutes 43471
What pressure will the falling snow exert on the roof of the house? The weight of snow on the entire roof is 150 kg. The area of the lookout, covered with snow, is 10 m². - Don't forget the notation; the formula then substitutes the result. - The square
The square oak board (with density ρ = 700 kg/m3) has a side length of 50 cm and a thickness of 30 mm. 4 holes with a diameter of 40 mm are drilled into the board. What is the weight of the board? - Cone-shaped 43291
Calculate the volume and weight of a pile of cone-shaped sand with a diameter of 8m and a height of v = 4.5m, the density of sand is 1500kg / M cubic - The aluminum
We placed the aluminum object with a weight of 0.80 kg and a temperature of 250°C in the water with a weight of 1.6 kg and a temperature of 23°C. What is the system temperature after reaching equilibrium? We assume that the heat exchange occurred only bet
- The bath
The bath has water with a volume of 220 l and a temperature of 65°C. Find the mass m2 of water at 15°C to be poured, so the resulting temperature in the bath will be 40°C. We neglect the heat exchange between water and the environment. The mass - Ten apples
The average weight of ten apples is 200 g. How does the average weight of apples change if we eat one apple weighing 129 g? - Six hens
Six hens weigh 3 kg more than three geese and 7 kg less than five geese. How much does a hen weigh, and how many geese? - Radiators
Calculate the radiator output if it has a thermal gradient (difference between inlet water and return temperatures) a) 5°C b) 10°C c) 15°C d) 20°C A heating water volume flow is 45 kg/h. How fast the water flows from the supply pipe to the radiator e) DN1 - Gravitational 41861
Find the potential gravitational energy of a 2000kg tow cage relative to the bottom of an 850m deep draw pit when the cage is on the surface.
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