Question

Find the magnitude of each of two vectors `veca` and `vecb` having the same magnitude such that the angle between them is 60° and their scalar product is `9/2`

Answer 1

Let the two vectors be `veca` and `vecb`

Since the vectors having same magnitude se,

`|veca| = |vecb|`

Scala product of the two vectors = `veca.vecb = |veca||vecb|cos theta`

`=> 9/2 = |veca||vecb| cos 60^@`

`=> 9/2 = |veca||vecb| xx 1/2`

`=> |veca||vecb| = 9`   (From (1))

`=> |veca|^2 = 9`

`=> |veca| = |vecb| = 3`