water flows through a pipe that gradually descends from a height of 6.78 m to the ground. near the top, the cross-sectional area is 0.4 m2, and the pipe gradually widens so that its area near the ground is 0.8 m2. water leaves the pipe at a speed of 16.8 m/s. what is the difference in the water pressure between the top and bottom of the pipe?

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