Energy - practice for 13 year olds - page 3 of 5
Number of problems found: 100
- 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 - Electrical 44931
A current of 20 A passes through the heating spiral of the electric fireplace with a resistance of 10Ω for 2.5 hours. Determine the power input of the fireplace and the consumed electrical energy - Consumption 44071
Calculate the electric motor's power if it works for 10 minutes, and the electricity meter measured the consumption of 500 Wh. - 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?
- 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 - Performance 41891
The car's engine develops a power of 1800N. Find its performance if it travels evenly on a horizontal path at 48 km/h. - 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. - Travels 41851
The car, with a weight of 20 kN, travels at a speed of 54 km/h. What is its kinetic energy?
- Average 41841
What work do we do if we pull out a 58mm nail with an average force of 350N? - Ethanol 39281
How much power can we get if we pour ethanol on a mini turbine from a height of 1.5 m Volume Ethanol 0.2m³. How much work does ethanol do? The casting time is 1.9 minutes. The density of ethanol is 789 kg/m². - Slices of ham
If 17 slices equal 70 calories, how many calories are in 5 slices? - Bricklayer 38291
A bricklayer will lay 12 m³ of brickwork in 4 days if he works 7 hours a day. How many days will he lay 51 m³ of masonry if he works 8.5 hours daily? - Constant 36941
The truck travels at a constant speed of 70 km/h. The first time it goes empty, and the second time it comes with a load. In which case is its kinetic energy smaller?
- Stroller 36521
Mom did a 5kJ job pushing the stroller. She always pushed him on the plane with a force of 50N. How far did she push the stroller? - Constant 36313
The truck weighs 4.5 tons and is moving at a constant speed of 72 km/h. How big is his kinetic energy? - Receiving heat
How many degrees Celsius was an iron cylinder weighing 300 g heated in a water bath if it received heat of 7.2 kJ? (specific heat capacity of iron c = 0.46kJ/kg/ºC) - Motorcycle engine
The motorcycle engine has a constant power of 1.2 kW for 0.5 hours. How much work does the engine do? Express work in kWh and Ws units. - Electric work
Calculate the work done by the electric forces passing the current of 0.2 A through the bulb in 10 minutes if the bulb is connected to a 230 V power supply.
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