Looking at the question I believe you mean America as a nation in the 1770s, after the revolution. The text is U.S. History Beginning to 1865, so you are focusing on the very beginning of America.
 
So lets start with Society:
Society changed in a number of ways. One the revolution meant that loyalty was now to the central government in the U.S. Not the King in England anymore. New jobs, in government and governmental affairs were created. After the revolution the West was open to explore. The "frontier" became popular and many people moved West to colonize new lands. 
 
People were not completely content with the new social order. One of the most famous rebellions was a slave rebellion (Nat Turner) that George Washington (as President) put down. Slavery was quickly becoming a more contentious issue. It was not just about the slave trade, but about whether the continued use of slaves, after the slave trade ended, should be allowed. There was also the issue of how to count a slave (or free black person) in census for representation. The South did not want to allow them rights, but the South did want them counted toward population because this would mean greater representation in Congress. Thus, they came up with the provision that black persons were "3/5 of a person." So the counted, just not as 1 person.
 
Also, as new states were created in the Frontier there grew the debate over whether they would be "free" states or "slave" states. Free states did not allow slaves, and Southern states wanted more slave states so they could influence Congress with pro-slavery agenda. As well as have new states to move to with their slaves. This created a divide and every time a territory wanted to become a state there was a debate. Eventually they settled on all states above the mason-dixon line were free and all south were slave owning. The territories allowed to become states was narrowed so as to keep the two as equal as possible.
 
political system
There were a lot of political changes going on as well. A governmental system had to be created. The first efforts were the Articles of Confederation written in 1777, ratified in 1781. However, they gave too much power to the States. They allowed the States to be independent and control their own affairs. The Federal Government could coin money and raise an army but did not have the ability to levy taxes, making it nearly impossible for them to have enough power to raise an army or settle any disputes.
 
By 1786 it was decided that the Articles of Confederation needed to be changed. In 1789 the Constitution was ratified. This gave far more power to the Federal Government and established the basis of the system we know today. The first 10 amendments were also drafted and ratified in conjunction with the Constitution.
 
There were debates on slavery and whether or not to continue it. In the end the slave trade was given a date to end, but the slaves already in the U.S. were still slaves. Also if they had children the children were slaves as well, thus the institution of slavery could continue. Issues regarding slavery (territories becoming states, representation in Congress, whether or not to count a black person as a whole person or not) were very important and growing political issues at the time.
 
economic industry
The North focused more on industry and factories, the South was more agrarian. The South relied heavily on slaves and relations with European countries who purchased their raw materials (cotton). The South was powerful in that most of the military academies were there, and many of the Presidents came from the South. The North was more progressive. They accepted new technology and thrived. The South lacked the ability to keep up with the North which fast become stronger economically than the South.
 
One debate that arose concerned railroads. There was a desire for a railroad service to be built stretching East to West. The question was whether to put it in the North or South. The South wanted it to transport their raw materials and grow their economies. But the North wanted it to promote their manufacturing. The North had a larger population and in the House of Representatives had a larger say. The North won the fight over the railroad.
 
A lot of the problems that showed up in politics, economy and society are linked. And as you can see a lot of them had to do with a growing North-South divide over the issue of slavery and economy.