Energy - math problems

Number of problems found: 66

  • What power
    radiator What power should the radiator have in a room 5x4 meters with a height of 3 meters? Hint: Calculate 35 watts per meter ^ 3 in case 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 defini
  • There
    watermixing There is 5 l of water with a temperature of 20°C in the bucket. We add 3 liters of hot water. The resulting temperature will be 30°C. What was the temperature of the hot water?
  • Thermometer
    energy Immerse a thermometer with a heat capacity of 2.0 J. K-1 in water weighing 67.0 grams. Before immersion in water, the thermometer showed a temperature of 17.8 degrees Celsius. After reaching equilibrium, the temperature is 32.4 degrees. What was the water
  • Latent heat
    ice How much heat is needed to take from 100 g of water at 20°C to cool to 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
  • The aluminum
    sphere_Nickel The aluminum object with a weight of 0.80 kg and a temperature of 250°C was placed in the water with a weight of 1.6 kg and a temperature of 23°C. What is the system temperature after reaching equilibrium? We assume that the heat exchange occurred only be
  • The bath
    watermixing The bath has water with a volume of 220 l and a temperature of 65°C. Determine the mass m2 of water at 15°C to be poured so that the resulting temperature of the water in the bath is 40°C. We neglect the heat exchange between water and the environment. T
  • Free fall
    freefall1 The elevator car weighing 720 kg is torn off at a height of 125 m and begins to fall in a free fall. How much kinetic energy does the elevator car have when it hits the ground floor of the building, when the free fall of the car lasted 5 s?
  • Slices of ham
    energy If 17 slices equals 70 calories how many calories are in 5 slices?
  • The bath
    watermixing Dad poured 50 liters of water at 60°C into the tub. How much cold water must be added at 10°C to obtain a bath that has a temperature of 40°C?
  • Electric cooker
    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
  • Harmonic oscillator
    kmity Calculate the total energy of a body performing a harmonic oscillating motion if its mass is 200 g, the amplitude of the deflection is 2 cm and the frequency is 5 Hz. Round the result to 3 decimal places.
  • Concrete column
    beton 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?
  • Receiving heat
    teplomer How many degrees Celsius was an iron cylinder weighing 300 g heated in a water bath if it received heat of 7.2 kJ? (specific heat capacity of iron c = 0.46kJ/kg / ºC)
  • Motorcycle engine
    motor_rpm 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.
  • Inclined plane
    naklonena_rovina 1. How much work W we have to do to pull a body weighing 200 kg along an inclined plane with a length of 4 m to a total height of 1.5 m. 2. Find the force we need to exert to do this if we neglect frictional resistance. 3. Find the force we would need if
  • Water mixing
    watermixing We have 520 ml of hot water and 640 ml of water at 48°C. What is the temperature of approximately hot water when the resulting mixture has a temperature of 65°C?
  • Electric work
    bulb 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.
  • The coal
    coal The coal stock would be enough to heat a larger room for 12 weeks, a smaller one for 18 weeks. It was heated for four weeks in both rooms, then only in a smaller one. How long was the coal stock enough?
  • Energy consumption
    elektromer The device is connected to 230V and draws 3.5A current. Power consumption is 1932kJ. How many minutes has this device been in operation?
  • Cooker
    kWMeter A current of 2A passes through the immersion cooker at a voltage of 230V. What work do the electric field forces in 2 minutes?

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