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 a and b is C and that angle between a and b is theta and that of a and C is alpha then the relation is given as,

tan alpha = (b sin theta)/(a + b cos theta)

Here, alpha = 40 degrees
b is unknown,theta = 110 degrees and a is 20 units

Putting all the values we get, b is 13.71 units

derivation of the formula is given below
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