A vector is formally, an element of a vector space. A vector has two components: a direction (or vector) component and a scalar component. For example, gravity is vector: the direction of gravitational force on the earth is towards the center of the earth and the scalar component is approximately 9.8 meters per second squared. As a rule of thumb, any thing that has both a quantity and a direction component can be represented with a vector. For example, velocity, acceleration, force, and momentum are all vectors. Speed and mass, on the other hand, are quantities without directions. They are not vectors but they are scalars. A scalar is a quantity without a direction. A scalar and a vector can multiply to produce a vector in the same direction as the original vector. For example, if a car heads west at 60 mph then a bus moving at...