The vectors a and b are given in terms of two perpendicular units vectors i and j on a plane by a = 2i – 3j, b = -i + 2j. Find the magnitude of the vector a + 3b
-
A.
2 -
B.
4 -
C.
(sqrt{10}) -
D.
35 -
E.
2.2
Correct Answer: Option C
Explanation
a = 2i – 3j – 3i + 6j
= -i + 3j
= (sqrt{5 times 2})
= (sqrt{10})