Question

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?

Answer 1

Please see the explanation below.

Explanation:

Apply the sine rule to the triangle formed by the `2` vectors `veca` and `vecb`and the resultant `vec(a)+vecb`

The triangle is an isoceles triangle.

The resultant is `||veca+vecb||=20u`

`||veca||=20u`

`||vecb||/sin40=||veca||/sin70=20/sin70`

`||vecb||=(20sin40)/sin(70)=13.7u`