Energy + power - practice problems - page 2 of 3
Number of problems found: 57
- 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? - 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. - 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. - Electric cooker
During which time, does an electric cooker with power input P = 500 W and with efficiency n = 75% heat water with mass m = 2 kg and temperature t1 = 10°C to the boiling point (t2 = 100°C). The specific heat capacity of water is c = 4 180 J. Kg-1. K-1 - 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? - 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. - Resistance 25021
Calculate the resistance and power of the appliance through which a current of 20mA flows at the mains voltage (230 V). - Energy consumption
The device is connected to 230V and draws a 3.5A current. Power consumption is 1932kJ. How many minutes has this device been in operation? - Transformer 20073
The transformer is oil-cooled and transforms a power of 20MW with an efficiency of 92%. Determine the temperature of the oil at the outlet of the transformer if the oil was 20°C when it entered the transformer. 2.5 liters of oil will flow through the tran - Surroundings 19153
A heating element with a resistance of 1.6 Ω is used to heat the car's rear glass. The body is connected to the battery in the car, which has a voltage of 12 V. a) What is the power input of the heating element? b) How much heat does the heating element g
- Weighing 12471
Compare the kinetic energy of a man weighing 80 kg who runs at a speed of 2 m/s and missiles weighing 20 g fired at 400 m/s. - Determine 12461
The 150t aircraft takes off at a speed of 288km/h and, after a while, reaches a speed of 900km/h. Determine the change in the kinetic energy of the aircraft. - Increased 12441
A car traveling at a speed of 25km/h increased the speed to a) 75km/h b) 100km/h when exiting the highway. How many times has its kinetic energy increased? - 3 phase load
Two wattmeters are connected to measure power in a 3 phase balanced load. Determine the total power and power factor if the two wattmeters read 1000 watts each (1) both positive and (2) the second reading is negative. - Friction coefficient
What is the weight of a car when it moves on a horizontal road at a speed of v = 50 km/h at engine power P = 7 kW? The friction coefficient is 0.07
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Energy - practice problems. Power - practice problems.