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If the sum of two unit vectors is a unit vector,then find the magnitude of their differences. |
Answer» Let `hat(n)_(1)` and `hat(n)_(2)` are the two unit vector. Then the sum is `vec(n)_(s)=hat(n)_(1)+hat(n)_(2)` or `n_(s)^(2)=n_(1)^(2)+n_(2)^(2)+2n_(1)n_(2) cos theta` `1+1+2 cos theta` Since it is given that `n_(s)` is also a unit vector,therefore `1=1+1+2 cos theta` or `cos theta =-1/2 or theta=120^(@)` now the diffrence vector is `n_(d)=n_(1)-n_(2)` or `n_(d)^(2)=n_(1)^(2)+n_(2)^(2)-2n_(1)n_(2) cos theta=1+1-2 cos (120^(@))` `:. n_(d)^(2)=2-2(-1//2)=2+1=3rArrn_(d)=sqrt(3)` |
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