- #1
gracy
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- 83
Homework Statement
Resultant of two vectors of equal magnitude A is
a) √3 A at 60
b) √2 A at 90
c) 2A at 120
d) A at 180
Homework Equations
When two vectors are of equal magnitudes then their resultant is
##A_R## = 2 A Cos θ/2
The Attempt at a Solution
I think we need more information especially the angle between the given two vectors . Or we can eliminate options one by one. Answer is both a & b
I tried to cross check it . If the resultant is at 60 it means angle between the vectors we started with is 120 i.e θ =120
if we plug in the numbers
##A_R## = 2A Cos 120/2
= 2A cos 60
= 2A 1/2
= A
which is not equal to √3
Similarly for option b
##A_R## = 2A Cos 180/2
= 2A cos 90
= 2A 0
= 0
I 'll get it correct if I directly put θ=60 & 90 respectively . But as far as I know θ in this formula ##A_R## = 2 A Cos θ/2 is angle between the two vectors and not the vector and resultant