Question

let a b c be the three vectors of magnitude 3, 4, and 5 respectively if one is perpendicular to the sum of the other two vectors, then |a + b + c | =


all a, b, c have bars​

Answer 1

Answer:

Given, a.(b+c)=0,b.(c+a)=0,c.(a+b)=0

Adding these, 2(a.b+b.c+c.a)=0 Also a

2

= a

2∣ =9,b

=25

Now (a+b+c)

2

=Σa

2

+2Σa.b=9+16+25+0+=50

∴∣a+b+c∣=5

2