A description of the short answer topics tested is on the ACSL category descriptions wiki. Many of the pages have links to YouTube videos that show solutions to sample questions.
Each contest in the Elementary Division consists of 5 short answer questions covering one topic each contest; the topic for each contest is listed below. The time limit for the 5-question test is 30 minutes. More information about this division is available in this presentation.
Each contest in the Junior, Intermediate, and Senior Divisions has two parts: a take home 72-hour time limit programming problem and a set of short answer questions. Each short answer test consists of 2 questions on each of the first two topics listed below and 1 question on the third topic for a total of 5 questions. The time limit for the 5 question test is 30 minutes.
Each contest in the Classroom Division consists of a 50-minute test with 10 short answer problems (and no programming problem). The topics are taken from the Junior, Intermediate, and Senior Division topics shown below.