Thanks in advance guys, and it does not need to be treated as a high priority question. 1. The problem statement, all variables and given/known data This is not so much a homework question, as it is a query about a question that I am getting a wrong answer for (that is to the book's answer). This is the straight question that the book gives me: "A student supplies a constant force of 200 N at an angle of 60 degrees to the horizontal to pull a 50 kg object, initially at rest across a flat surface for 10 s. A constant frictional force acts on the mat, and the velocity after the 10 s is 3 ms-1" The question asks how much work is done on the mat by the student? 2. Relevant equations [tex]W = F * x * cosine (theta)[/tex] 3. The attempt at a solution I have substituted the values for cosine theta as 0.5, and F is 200 N, I tried to find the value for x, by using v * t = x, and substituted it as 3 * 10 = 30 m. The answer that I found was 6 * 103 joules, and the book gave the answer as 1.28 * 103.