# Power + energy - math problems

Power is the amount of work done (energy supplied) per unit time. In physics, power is the amount of energy transferred or converted per unit time. In the SI units, the unit of power is the watt, equal to one joule per second. Other units are, for example, 1 hp (one horsepower; 1 hp = 735.5 W) and then derived units such as kW - kilowatt.#### Number of problems found: 15

- 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 m^{3}/s is supplied with a flow rate of h = 70.5 m at full power. a) What is the total installed power of the p - Decibel

A circuit has an input power of 58 mW. Its output power is 6 mW. What is the loss in decibels? - 3 phase load

Two wattmeters are connected to measuring 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) second reading is negative - Energy consumption

The device is connected to 230V and draws 3.5A current. Power consumption is 1932kJ. How many minutes has this device been in operation? - Motor physics

Car traveling at 130 km/h on the highway. Pulling power of the motor is 8 kN. Determine engine power in kW. - Efficiency

What is the power output of kettle 2 kW with efficiency 90%? - 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 =? - Pump

What power has a pump output to move 4853 hl of water to a height of 31 m for 8 hours? - 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. - 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. - Concrete column

The concrete column of the highway bridge has the shape of a block with dimensions of 1m x 0.8m x 25m. It should be lifted by crane to a height of 20m. What is the power of his engine if the lifting takes 2 minutes? - Stand-by power

Determine the year-round consumption of appliances in stand-by mode. Stand-by mode is regime the unit continuously 24 hours consume a tiny amount of electricity. Typically are televisions, electric ovens, radios, computers, monitors, satellite receivers, - Electric cooker

During which time t 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 - 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 - Elevator

In homes with more floor 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 coun

Do you have an interesting mathematical word problem that you can't solve it? Submit a math problem, and we can try to solve it.

See also more information on Wikipedia.