A frame of reference is a point or set of fixed points relative to an object describing a motion, and affects on the movement you perceive for the object.
For example, if you throw a stone from the window of a car, you'll see a different trajectory depending on whether you take the road or the car as the frame of reference. On the first situation you'd notice a trajectory, while from the car you'd see the stone almost falling to the ground only.
Answer:
Louisiana purchase entailed negative consequences for most of the Louisiana population - blacks and Indians - and became one of the causes of acute social contradictions in modern America. In just 30 years, Americans ousted Indians from most of the Mississippi Valley, physically destroying or expelling them from their ancestral lands through fraudulent treaties.
Explanation:
Philadelphia and Hartford
No, generally speaking <span>African Americans would not have been eager to fight for the United States during the Spanish American War, since they were treated with such disrespect by white Americans, who started the war in the first place. </span>