The maximum weight for a U.S. semi truck and full trailer is 80,000 pounds spread over 18 conventional wheels. Out in the wide-open spaces of Australia, however, road trains can have four trailers and weigh in excess of 300,000 pounds.
Types of academic source. Sources such as newspaper articles, magazine articles, opinion pieces, and websites are not commonly academic, although there are some exceptions. Many journal articles and reports can be found online, for example. Academic journals are very different from popular magazines, although they bear several similarities.
For every source you use, you will need to think of the questions above to determine which category they fit into - primary or secondary - and how much you can trust what they say. Primary Sources Primary sources are informational sources from the time of the event. 1  Examples of primary sources: 2  Autobiographies. 3  Diaries. 4  Documents. 5  Eyewitness accounts. 6  Film footage. 7  Laws. 8  Letters. 9  Newspaper articles. 10  Novels. 11  Objects from the time. 12  Oral histories. 13  Photographs. 14  Poems, art, music. 15  Speeches.