List two examples of ways to increase efficiency in a machine.

Apositive rod is placed to the left of sphere a, and the spheres are separated. which best describes the spheres? sphere a is negative and sphere b is positive because protons from sphere a are attracted to the rod and move to sphere b. sphere a is negative and sphere b is positive because electrons from sphere b are attracted to the rod and move to sphere a. sphere a is positive and sphere b is negative because electrons from the rod move to sphere b and protons then move to sphere a. sphere a is positive and sphere b is negative because protons move from sphere b to the rod and also to sphere a.

Aregion of space in which a measurable gravitational force is indicated by the force exerted on a test mass is called

Abowling ball rolling down the lane toward the pins has gravitational potential energy. a. no b. a lot of c. a little