Energy = Power x Time

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Across
  1. 1. A motor in a helicopter lifts up a person. To lift up person up to the helicopter, the electric motor transformed 21 600 joules of energy usefully. It takes 50 seconds for the electric motor to lift the person up to the helicopter. Calculate the power of the motor.
  2. 3. An electric motor is supplied with 108000 J of electrical energy. The motor works for 2 hours. Calculate the power of the motor.
  3. 4. A car engine has an output power of 150 kW and an input power of 200 kW. What is its efficiency as a percentage?
  4. 6. A solar panel with a power output of 300 W is used to charge a battery for 6 hours. How much chemical energy does the battery store in joules?
  5. 7. A television is supplied with 60 000 J of electrical energy. The television is on for 20 s. Calculate the power of the TV in watts.
  6. 9. What is 5 kW in W?
  7. 10. A person uses 24000 J of energy to walk up a flight of stairs in 120 seconds. What is the person's average power in Watts?
  8. 11. How long will it take (in seconds) for a 100 W light bulb to transfer 6000 J of energy?
Down
  1. 2. A 1200 W hair dryer is used for 30 minutes. How much energy does it transfer in joules?
  2. 4. What is 2 hours in seconds?
  3. 5. What is the energy used by a 80 W light bulb in 1 minute in joules?
  4. 6. A light bulb has an output power of 60 W and an input power of 100 W. What is its efficiency as a percentage?
  5. 8. A car engine with a power of 150 kW uses 108,000,000 J of energy. How long will it be running in seconds?