Question

Two vectors A and B are at right angles to each other. The magnitude of A is 3.00. What should be the length of B, so that the magnitude of their vector sum is 5.00?

Answer 1

Answer: length of B =4.00

Explanation:

for  the vectors A and B and the angle between them as  x.

Magnitude of the sum of A and B is  given as = √(A²+B²+2ABcosx

where

Magnitude of A  = 3.00

Magnitude of the sum of A and B is  5.00

5.00=√(A²+B²+2ABcos90°

5.00= √3² +b² +0

5²= 3² +b²

25=9+b²

b²= 25-9

b² = 16

b=  √16

b= 4