Question

if the sum of two unit vectors is also a unit vector the angle between the two given unit vectors is

Answer 1

Answer:

120 degrees

Explanation:

${1}^{2} + {1}^{2} + 2 \times 1 \times 1 \times \cos( \alpha ) = 1$

because magnitude of unit vectors is 1

on further calculation

cos

$\cos( \alpha ) =$

-1/2

so alpha is 120 degrees

Answer 2

Answer: 120 degrees

Explanation:

{1}^{2} + {1}^{2} + 2 \times 1 \times 1 \times \cos( \alpha ) = 1

because magnitude of unit vectors is 1

on further calculation

cos

\cos( \alpha ) =

-1/2

so alpha is 120 degrees