Two vectors from an angle of 110°. One of the vectors is 20 units long and makes an angle of 40° with the vector sum of the two. Find the magnitude of the second vector and of the vector sum?

1 Answer
Jan 15, 2018

13.71 units

Explanation:

If the sum of two vector aa and bb is CC and that angle between aa and bb is thetaθ and that of aa and CC is alphaα then the relation is given as,

tan alphatanα = (b sin theta)/(a + b cos theta) bsinθa+bcosθ

Here, alphaα = 40 degrees
bb is unknown,thetaθ = 110 degrees and aa is 20 units

Putting all the values we get, bb is 13.71 units

derivation of the formula is given below
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