Question
Two vectors acting in opposite direction have resultant 7 units and if they act at angle 90° to each other, the resultant is 13 units. Calculate the magnitude of the two vectors.
Solution
Let A and B be the magnitude of two vectors and let A>B.
When act in opposite direction, the magnitude of resultant is A - B
Now,
A - B = 7 [Given] ...(1)
When act perpendicular to each other, then their resultant is,
...(2)
Now,
∴
and
or ...(3)
On solving equation (1) and (3), we get
A = 12 and B = 5