Power + fundamentals of Physics - practice problems
Number of problems found: 64
- The intensity
The light intensity on a screen is inversely proportional to the square of the distance between the screen and the light source. If a screen is illuminated by a light source 20 m away, the intensity is one-fifth of what is required. Where should the light - Heat energy
Energy is measured using the unit Joule (J). Temperature is measured using the unit degree Celsius °C). To increase the temperature of 1 liter of water by 1°C, 4200 J of heat energy is required. (a) Kelly wants to increase the temperature of 2 liters of w - Electrical 82513
How long will it take for a current of 8A in a resistance of 30 ohms to develop thermal energy of 3 MJ if the efficiency of converting electrical energy into heat is 90%? - Horizontal 82197
A cyclist rides along a horizontal path at a constant speed, overcoming a total resistance force of 20 N. What work does he do on a 5 km track? - 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? - Effectiveness 80711
When testing the effectiveness of an electric cooker with data of 220 V, 1200 W, 1 kg of water at a temperature of 15 degrees Celsius was boiled for 8.5 minutes. Calculate the stove efficiency corresponding to these data - Automatically 80704
The electric circuit breaker automatically switches off the circuit of the 220 V electrical network at a current of 6 A. Determine the maximum power in the protected circuit. - 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? - Consumption 80702
A current of 500 mA passed through the filament of a light bulb with a resistance of 400 ohms. What is the consumption of a light bulb in 5 hours? - Electrical 80549
The factory hall is lit by 76 light bulbs, each of which has an input of 200W. Determine how much electrical work will be saved annually if the light is on an average of 100 minutes less per day. Consider 260 business days. - Instantaneous 76754
For a dipole, calculate the complex apparent power S and the instantaneous value of the current i(t), given: R=10 Ω, C=100uF, f=50 Hz, u(t)= square root of 2, sin( ωt - 30 °). Thanks for any help or advice. - What power 2
What power has a pump output to move 4853 hl of water to a height of 31 m for 8 hours? Comparing the power generated by the pump vs. the power generated by the motor, which is more efficient? Which pump or motor generates more pollution if, for every watt - Which 10
Which will have greater momentum between a ten-wheeler truck weighing 7,000 kg and a bus that weighs 5,000kg if the bus is moving at 15 m/s while the truck is moving at 10 m/s? - Cross-section 71254
The steel conductors of the long-distance power line have a cross-section of 5 cm². Calculate the resistance of a steel wire with a length of 2 km if the resistivity of the steel is 13 * 10-8 Ω · m. - Power during takeoff
The aircraft weighing 3.5 tons will disembark 1 km in 1 minute after takeoff and reach a speed of 290 km/h. Find the average power of its engines during this time. - Pump power
Determine the pump power if: I pour 3 m³ of water from the tank in 120 seconds with a hose. The height of the hose mouth above the tank is 1.5 m. The water's speed from the hose outlet is 20 m/s. - Increasing 69094
The aircraft weighs 61 tons. It climbed from a height of 1000 m to a height of 3000 m while increasing the speed from 170 m/s to 210 m/s. What work did the aircraft engines do? - Instantaneous 69064
Describe how the instantaneous power value in the AC circuit changes during one period. - A fan
A fan with a resistance of 20 Ω is connected to a power supply. The current flowing through the circuit is 2.5 A. What is the voltage of the power supply? - Transfers 67414
At 80 cm above the road, a person transfers a stone weighing 2 kg parallel to it in a uniform motion along a path of 6 m in 10 s. With what power does it work?
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