The means which one uses to motivate others and achieve one's goals plays a key role in distinguishing between effective leaders and ethical leaders.
Ethical leaders main focus is on imparting morally acceptable values to his members and ensure they live by it. An ethical leader makes for moral staff than focus on motivating others.
On the other hand and effective leader is all encompassing, he incorporates leadership principles that motivates people and make them put in their best in order to achieve his his goals. The effective leader does anything that will make the people feel motivated and bring put the best in them.
Due to the external atmospheric pressure. Initially the pressure inside the can is balanced by the atmospheric pressure. But as the air is removed from inside, the external pressure dominates.