Astudent lifts a set of books off a table and places them in the upper shelf of a book case which is 2 meters above the table. if she applies a force of 5 newtons to lift these books, what is the work done?

Work (W) is the product when we multiply the force applied (F) and the displacement (d). The displacement and the force applied should be in the same direction for the force to be done. 
                                       W = F x d
Substituting the given values,
                                        W = (5 N) x (2 m) = 10 Nm
Therefore, the work done is 10 J. 

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.