When can the sum of two vectors be said to be greater
When the two vectors act in opposite directions
Both vectors act in the same direction
When both the vectors are at right angles
None of the Above.
Option(b) is correct because Two vectors have the same direction if they are parallel and point in the same direction. If one vector is a positive scalar multiple of the other, then the two vectors have exactly the same direction .
Option (a) is incorrect because two vectors of opposite orientation but of equal magnitude cancel out and yield a zero vector.
Option (c) is incorrect because Marshall said that when a pair of vectors are at right angles to each other, the magnitude of their combined force is greater than the magnitude of either the other vector alone.