Point 1: For case for ground pin. Also ground pin is larger that other two pins so that it would be the first to go into the hole and the last to come out of the hole just for sake of safety Point 2:...
Let us solve Irodov problem 1.1 on Kinematics. The problem states: A motorboat going downstream overcame a raft at a point A; τ=60 min later it turned back and after sometime passed the raft...