Which equation represents the law of conservation of energy in a closed system?

KEi + PEi = KEf + PEf
PEi + PEf = KEi + KEf
KEi – KEf = PEi – PEf
KEi – PEf = PEi – KEf

Explanation:

A closed system is a system where exists energy interactions with surroundings, but not mass interactions. If we neglect any energy interactions from boundary work, heat, electricity, magnetism and nuclear phenomena and assume that process occurs at steady state and all effects from non-conservative forces can be neglected, then the equation of energy conservation is reduce to this form:

(1)

Where:

- Change in kinetic energy of the system, measured in joules.

- Change in gravitational potential energy of the system, measured in joules.

If we know that and , then we get the following equation:

(2)

Where and stands for initial and final states of each energy component.

Hence, the right answer is

answer: d. a cme increases the amount of energy in the solar wind

explanation:

coronal mass ejections, also called cmes, are large clouds of plasma and magnetic field that erupt from the sun. only when the cloud is aimed at earth will the cme hit earth and therefore cause impacts. high-speed solar wind streams come from areas on the sun known as coronal holes.

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.