Let a be a vector of magnitude 4.5 unit pointing due north. Evaluate the vector -4 a .

Step-by-step solution

Given | a | = 4.5 units and its direction is due north. The magnitude of the vector -4 a is |-4 a | = |-4| | a | = 4 4.5 = 18 units. The negative sign indicates that the direction of -4 a is opposite to the direction of a . Since a points due north, -4 a points due south. Thus, -4 a is a vector of magnitude 18 units pointing due south.