1. The problem statement, all variables and given/known data A motor car with a 'flat' battery can be started by connecting jumper leads from the battery to the leads of another car battery. To do this, the two positive terminals and the two negative terminals must be connected together. 1) Why is this? 2) Are the two batteries in series or are they parallel? 2. Relevant equations none 3. The attempt at a solution 1) The dead battery has the positive and negative terminals at the same potential. So when a working battery connects its positive end to the positive end of a dead battery and negative to negative, a current will flow from positive to positive of dead battery. Current (using postive charge always, reverse for electrons) will flow from negative of dead battery to negative of good battery since the potental in the negative of dead battery is greater than potential of negative of good battery. Overall, this will mean higher potential at positive end of dead battery (because more charges are there now) and lower potential at negative end of dead battery (because charges which were there have migrated to the other good battery) meaning a restoration of the dead battery. However, this is done at the expense of the good battery as its PD is smaller as a result. 2) The two batteries are connected in series?