An ant is crawling along a straight wire, which we shall call the $x$ axis, from $A$ to $B$ to $C$ to $D$ (which overlaps $A ),$ as shown in Figure $2.39 . O$ is the origin. Suppose you take measurements and find that $A B$ is $50 \mathrm{cm}, B C$ is $30 \mathrm{cm},$ and $A O$ is 5 $\mathrm{cm}$ . (a) What is the ant's position at points $A, B, C,$ and $D ?$ (b) Find the displacement of the ant and the distance it has moved over each of the following intervals: (i) from $A$ to $B,$ (ii) from $B$ to $C,$ (iii) from $C$ to $D,$ and (iv) from $A$ to $D$ .