Which of the following will increase the force of gravity between two charged objects without affecting the electric force?
a. increasing the distance between the objects
b. increasing the charge of both objects
c. increasing the gravitational constant
d. increasing the mass of one object

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