Energy - practice for 14 year olds - page 3 of 5
Number of problems found: 100
- 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 - Free fall
The elevator car weighing 720 kg, is torn off at the height of 125 m and begins to fall in a free fall. How much kinetic energy did the elevator car have when it hit the ground floor of the building when the free fall of the car lasted 5 s? - 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? - Concrete column
The concrete column of the highway bridge has the shape of a block with dimensions of 1m x 0.8m x 25m. Crane should lift it to a height of 20m. What is the power of his engine if the lifting takes 2 minutes? - 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. - Water mixing
We have 520 ml of hot water and 640 ml of water at 48°C. What is the temperature of approximately hot water when the resulting mixture has a temperature of 65°C? - 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. - Resistance 25021
Calculate the resistance and power of the appliance through which a current of 20mA flows at the mains voltage (230 V). - The coal
The coal stock would be enough to heat a larger room for 12 weeks and a smaller one for 18 weeks. It was heated for four weeks in both rooms, then only in a smaller one. How long was the coal stock enough?
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Energy - practice problems. Maths practice for 14 year olds.