Answer
K = 3.00 J
Work Step by Step
From the previous problem (81b), we got that at x = 2.00 m, K = 9.00 J and U = 5.00 J. As the particle gets to x = 0, it will be acted on by $F_{1}$ = +3.00 N from x = 2.00 m to x = 0, which is a displacement d = – 2.00 m. Therefore, the force will do a work W = $F_{1}$d = (3.00 N)(–2.00 m) = –6.00 J, which represents the change in kinetic energy. Therefore, at x = 0, K = 9.00 J + (–6.00 J) = 3.00 J.
