Energy + power - practice problems - last page
Number of problems found: 57
- Performance 7737
Zdenek, weighing 54 kg, made 15 push-ups on the crossbar. The height he reached was about 40 cm. What kind of work did he do? What was his performance if the whole exercise took him a minute and a half? - Temperature 7595
Colorless liquid weighing m = 200 g is heated with constant stirring on a stove with power input P0 = 600W. 80% of the supplied energy is used to heat the liquid. Selected measured values of liquid temperature as a function of time are recorded in the t - Resistance 7503
The resistance of a 40W light bulb is 10 Ohms. What voltage source is connected to it? What current is flowing through it? - Orlík hydroelectric plant
The Orlík hydroelectric power plant, built in 1954-1961, consists of four Kaplan turbines. For each of them, the water with a flow rate of Q = 150 m3/s is supplied with a flow rate of h = 70.5 m at full power. a) What is the total installed pow
- Electric input power
Solve problems related to electric power: a) U = 120 V, I = 0.5 A, P =? b) P = 200 W, U = 230 V, I =? c) I = 5 A, P = 2200W, U =? - Refrigerator 6703
Calculate how much we will pay for 1 hour of consumed electrical energy if the seller sets a price of 0.126 euros for 1 kWh (all appliances together for 1 hour of work). Table: Appliance Power (W) Washing machine 2300 W Bulb 40W Refrigerator 200W TV 110W - Electricity 6667
A light bulb with power consumption P = 70 W. It is connected to a mains voltage of 230 V. How big is the electric current that flows through it? How much electricity in kWh will it use if it is on for 9 hours 30 minutes? - Consumption 6581
We heated water weighing 1 kg at 70 degrees in a kettle. C. In 5 min. What is the power consumption of the kettle? We do not take into account losses or boiling points. - Electric 5914
A current of 2 A at a voltage of 400 V passes through the electric motor. The electric motor is switched on for 0.5 h. What is the power input of the electric motor?
- The appliance
The appliance has a power input of 2.3 kW. It is connected to the mains voltage of 230 V. What is the current flowing through the appliance? - Efficiency 4073
Determine the efficiency of a vacuum cleaner with a power input of 1.2 kW when the suction power is 360 W. - Efficiency
What is the power output of a kettle 2 kW with an efficiency of 90%? - Elevator
In homes with more floors, elevators are used. For passenger transport, the most commonly used traction elevator counterweight. The top of the shaft engine room with the engine. The car is suspended on a rope, which is guided up over two pulleys to the co - Motor physics
A car is traveling at 98 km/h on the highway. The pulling power of the motor is 6 kN. Find the engine power in kW.
- Decibel
A circuit has an input power of 92 mW. Its output power is 12 mW. What is the loss in decibels? - Stand-by power
Determine the year-round consumption of appliances in standby mode. Standby mode is a regime in the unit continuously for 24 hours and consumes a tiny amount of electricity. Typically are televisions, electric ovens, radios, computers, monitors, satellite - Pump
What power does a pump output to move 4853 hl of water to a height of 31 m for 8 hours?
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