Resultant of #vecP# and #vecQ# is equal to the value of #vecP#.Prove that,resultant of #2vecP# and #vecQ# is perpendicular to #vecQ#?

1 Answer
Jul 16, 2017

See below.

Explanation:

If #norm(vec P+vec Q) = norm(vec P)# then

#norm(vecP)^2+2 << vec P, vec Q >> + norm(vec Q)^2 = norm(vec P)^2#

Here #<< cdot, cdot >># indicates the scalar product of two vectors.

then

#norm (vec Q)^2+2 << vec P, vec Q >> = 0# or

#<< vec Q, 2 vecP + vec Q >> = 0#

so

#vec Q# and #2 vec P+ vec Q# are perpendicular..