Energy + unit conversion - practice problems
Number of problems found: 44
- Mechanical 83220
An airplane weighing 100 tons flies at an altitude of 11 km at a speed of 850 km/h. What is its kinetic, potential, and total mechanical energy? - 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%? - Coefficient 81094
A car moves along a horizontal road at a speed of 15 m/s. After turning off the engine, the car traveled a distance of 225 m. What was the coefficient of friction for this motion? - Calculate 80550
A cheetah weighing 38 kg moves at a speed of 108 km/h. Calculate its kinetic energy
- 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. - 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 - Increases 69454
The car weighs 1850 kg and increases its speed from 27 to 81 km/h. How much has its kinetic energy increased? - 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. - Performance 66404
A person weighing 50 kg can climb 15 stairs. One step is 18 cm high. Determine a person's performance when: a) slowly climbing the stairs if it took him 13 seconds b) going down the stairs slowly if it took him 10 seconds c) quickly climbing the stairs if
- Power consumption
The price of electricity is ₱6.50 per kilowatt hour (kWh). How much electricity was consumed if a television with 120 W power consumption ran from 7:30 AM to 12:30 PM? How much will this cost? - Lead melt
Find the heat needed to melt an object made of lead weighing 250g and an initial temperature of 35°C. Lead melts at 327°C at normal pressure. Mass heat capacity of lead c = 129 J/kg • K and mass latent heat of lead lt (t is the subscript) = 22.6 kJ/kg. - What power
What power should the radiator have in a room 5x4 meters with a height of 3 meters? Hint: Calculate 35 watts per meter³ when you need 22 degrees in the room, but you need about 24 degrees in the bathroom. It's an old heating cheat, but it will help you. - Thermometer
Immerse a thermometer with a heat capacity of 2.0 J. K-1 in water weighing 67.0 grams. Before water immersion, the thermometer showed a temperature of 17.8 degrees Celsius. After reaching equilibrium, the temperature is 32.4 degrees. What was the water te - Latent heat
How much heat is needed to take from 100 g of water at 20°C to cool to the ice at -18°C? Mass heat capacity c (ice) = 21kJ/kg/°C; c (water) = 4.19 KJ/kg/°C and the mass group heat of solidification of water is l = 334kJ/kg
- Cylindrical 46021
Calculate the magnetic field energy of a cylindrical coil with 400 turns, a length of 0.4 m, and a radius of 20 mm. A current of 3A passes through the coil. (µo = 4π 10-7 H. M-1) - 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? - Radiators
Calculate the radiator output if it has a thermal gradient (difference between inlet water and return temperatures) a) 5°C b) 10°C c) 15°C d) 20°C A heating water volume flow is 45 kg/h. How fast the water flows from the supply pipe to the radiator e) DN1 - Average 41841
What work do we do if we pull out a 58mm nail with an average force of 350N?
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