What happens to hotter air in the atmosphere? A. Warmer air molecules move faster and get farther apart. As they get farther apart, they become more dense and sink.

B. Warmer air molecules move faster and get farther apart. As they get farther apart, they become less dense and rise.

C. Warmer air molecules move slower and spread out. As they spread out, they sink below cooler air molecules.

A75-hp (shaft output) motor that has an efficiency of 91.0 percent is worn out and is to be replaced by a high-efficiency motor that has an efficiency of 95.4 percent. the motor operates 4368 hours a year at a load factor of 0.75. taking the cost of electricity to be $0.12/kwh, determine the amount of energy and money saved as a result of installing the high-efficiency motor instead of the standard motor. also, determine the simple payback period if the pu