Time + energy - practice problems
Number of problems found: 68
- Determine 80705
The bulb is rated 6 V, 0.2 A. Determine the current rating of the bulb. - Efficiency 4072
What kind of work did the mixer with an efficiency of 30% do when it did 4.5 kWh of work? - Workers 7767
Twelve workers would earn € 800 in 10 days. How many euros would 14 workers earn in 8 days? - Weighing 12481
A stone weighing 200g falls in a free fall for 3 s. Find its kinetic energy on impact. - Bulb
A 60 W bulb consumes 0.12 kWh of electricity. How long did she stand light without a break? - Pump
What power does a pump output to move 4853 hl of water to a height of 31 m for 8 hours? - Resistance 80700
Determine the largest voltage on a resistor with a resistance of 150 ohms if the largest permitted electrical power current in the resistor is 2 W. - Resistance 25021
Calculate the resistance and power of the appliance through which a current of 20mA flows at the mains voltage (230 V). - Cooker
A current of 2A passes through the immersion cooker at a voltage of 230V. What work do the electric field forces do in 2 minutes? - Consumption 44071
Calculate the electric motor's power if it works for 10 minutes, and the electricity meter measured the consumption of 500 Wh. - 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? - 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. - Kilowatt-hours
If the Lewis family used 648 kilowatt-hours of electricity in 12 days, how many kilowatt-hours should they use in 24 days at the same usage rate? - Cows
Twenty cows have food for 60 days. We reduce the dose to two-thirds for 18 cows. How many days will it feed? - ELECTRICAL 81742
A cooker connected to a 40 V voltage source draws a current of 0.5 A. DOES THE SIZE OF THE ELECTRICAL WORK DETERMINE WHICH COOKER DOES IN 3 MINUTES? - Identical 2804
Eighty identical light bulbs shine in the sports hall for two hours. How long does it take to consume the same energy from 100 such bulbs? - Resistance 80703
An immersion cooker has a resistance of 30 ohms and is connected to a voltage of 120 V. How much heat is generated in 2 hours? - Harmonic oscillator
Calculate the total energy of a body performing a harmonic oscillating motion if its mass is 200 g, the deflection amplitude is 2 cm, and the frequency is 5 Hz. Please round the result to 3 decimal places. - 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. - 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.
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