Is the following measurement a vector quantity or a scalar quantity? 68 km south

vector quantity

explanation:

the quantities which are completely described by their magnitude only are called scalar quantities. for example, mass, time, length, etc.

the quantities which are completely described by their magnitude and direction both are called vector quantities. for example, weight, force, displacement, velocity, etc.

here, it is 68 km south, it shows a direction is given so it s a vector quantity.

conservation of mass

mass before something happens = mass afterwards