Answer
(a) $W = -5.4~J$
(b) $W = -5.4~J$
(c) $W_{total} = -10.8~J$
(d) The friction force is nonconservative.
Work Step by Step
(a) $W = -F_f~d$
$W = -(1.8~N)(3.0~m)$
$W = -5.4~J$
(b) $W = -F_f~d$
$W = -(1.8~N)(3.0~m)$
$W = -5.4~J$
(c) $W_{total} = -5.4~J - 5.4~J$
$W_{total} = -10.8~J$
(d) I would say that the friction force is nonconservative. The starting point and ending point of the book's journey are the same point but the total work done on the book by the friction force is not zero. Therefore, the friction force is nonconservative.
