An elevator's electric hoist is rated at 8.0 kw and has an efficiency of 90.0%. the hoist lifts the elevator car, mass 1225 kg, a distance of 9.00 m. (a) how much time is required? (b) how much electrical energy is used to perform this task?

Which of the following best describes internal energy? a. the difference between the kinetic and potential energies of the particles in a system b. the sum of the kinetic and potential energies of the particles in a system c. the sum of the kinetic and thermal energies of the particles in a system d. the difference between the kinetic and thermal energies of the particles in a system