A 1.00 -kg block is pushed up and down a rough plank of length $L=2.00 \mathrm{~m},$ inclined at $30.0^{\circ}$ above the horizontal. From the bottom, it is pushed a distance $L / 2$ up the plank, then pushed back down a distance $L / 4,$ and finally pushed back up the plank until it reaches the top end. If the coefficient of kinetic friction between the block and plank is $0.300,$ determine the work done by the block against friction.