This chapter initially explains the difference between scalar and vector quantities and shows how a vector is drawn and represented. Any object that is acted upon by an external force will respond to that force by moving in the line of the force. However, if two or more forces act simultaneously, the result is more difficult to predict; the ability to add two or more vectors then becomes important. This chapter thus shows how vectors are added and subtracted, both by drawing and by calculation, and finding the resultant of two ormore vectors hasmany uses in engineering. (Resultant means the single vector which would have the same effect as the individual vectors.) Relative velocities and vector i, j, k notation are also briefly explained.