Energy - practice problems - page 5 of 11
Number of problems found: 207
- Brick lifting work
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) = 21 kJ/kg/°C; c (water) = 4.19 KJ/kg/°C and the mass group heat of solidification of water is l = 334 kJ/kg - Cylindrical magnets
Calculate the magnetic field energy of a cylindrical coil with 400 turns, a length of 0.4 m, and a radius of 20 mm. A current of 3 A passes through the coil. (µo = 4π 10-7 H/m) - Fireplace power consumption
A current of 20 A passes through the heating spiral of the electric fireplace with a resistance of 10 Ω for 2.5 hours. Determine the power input of the fireplace and the consumed electrical energy - Cathedral roof sphere
Cathedral height is 110 m, sphere weight 6000 kg, dome diameter 43 m, crane arm length 25 m a) what was the diameter of this sphere? b) how much mechanical work had to be done to lift it to the designated place? - Transmission of electricity
The electric field performs work 1610 J in the transmission of electric charge of 7 Coulombs between the heating coil terminals. Calculate the voltage between the terminals. - Motor power
Calculate the electric motor's power if it works for 10 minutes, and the electricity meter measured the consumption of 500 Wh. - Crane lifting time
The crane motor has a constant power of 9 kW. With constant movement, how long does it take to lift a body weighing 12 tons to a height of 9 m? - Body energy
A body weighing 2 kg falls from a height of 45 m in a free fall. What will be its potential energy and total mechanical energy after 2 s from the beginning of the movement? - The aluminum
An aluminium object weighing 0.80 kg at 250 °C is placed in 1.6 kg of water at 23 °C. What is the equilibrium temperature of the system? Assume that heat exchange occurs only between the aluminium object and the water. The specific heat capacity of alumin - 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. Water - Elevator potential energy
The elevator cabin weighing 720 kg goes from the ground floor to the top floor of the building, at 125 m. How much potential energy does the elevator cabin have on the top floor of the building - at the height of 125 m? - 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) - 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?
- Engine performance
The car's engine develops a power of 1800 N. Find its performance if it travels evenly on a horizontal path at 48 km/h. - Cage gravitational energy
Find the potential gravitational energy of a 2000 kg tow cage relative to the bottom of an 850 m deep draw pit when the cage is on the surface. - G Force, mass A car with a weight of 20 kN travels at a speed of 54 km/h. What is its kinetic energy?
- Nail work
What work do we do if we pull out a 58 mm nail with an average force of 350 N? - Ethanol turbine
How much power can we get if we pour ethanol on a mini turbine from a height of 1.5 m Volume Ethanol 0.2 m³. 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?
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