(a) Event $A$ happens at point $\left(x_{A}=5, y_{A}=3, z_{A}=0\right)$ and at time $t_{A}$ given by $c t_{A}=15$ event $B$ occurs at (10,8,0) and $c t_{B}=5,$ both in system $\mathcal{S}$
(i) What is the invariant interval between $A$ and $B ?$
(ii) Is there an inertial system in which they occur simultaneously? If so, find its velocity (magnitude and direction) relative to $\mathcal{S}$
(iii) Is there an inertial system in which they occur at the same point? If so, find its velocity relative to $\mathcal{S}$
(b) Repeat part (a) for $A=(2,0,0), c t=1 ;$ and $B=(5,0,0), c t=3$