1. A 2 kg book is at rest on a flat frictionless surface at initial position xi=0. A force F= (2.5-x2) is applied on the book. What is the Kinetic Energy of the block as it passes through x=2 m ? 2. W= Int ( force ) ; K= (1/2)mv2 ; W = K1 - K2 3. So I started out with finding the W by taking the integral of F from x=0 to x=2. Then i put the value of the work in the work-kinetic energy equation. And im stuck here cause i don't know where to use the mass of the book.