SAT考试是美国高中生进入美国大学的标准入学考试，包括SAT1和SAT2。SAT2是专项测验，有数学、物理、化学、生物、外语等，大部分为选择题，是可以选科的。今天我们来学习SATII物理专题分析 Vector Multiplication，希望对大家的复习有所帮助。

　　There are two forms of vector multiplication: one results in a scalar, and one results in a vector.

　　Dot Product

　　The dot product, also called the scalar product, takes two vectors, “multiplies” them together, and produces a scalar. The smaller the angle between the two vectors, the greater their dot product will be. A common example of the dot product in action is the formula for work, which you will encounter in Chapter 4. Work is a scalar quantity, but it is measured by the magnitude of force and displacement, both vector quantities, and the degree to which the force and displacement are parallel to one another.

　　The dot product of any two vectors, A and B, is expressed by the equation: