Question

Two forces of 5 Newton each act at point inclined at 120° with each other. The magnitude of vector addition of these forces is:

Answer 1

net=√(50+50cos120)

=√(50-25)

=5 newton

Answer 2

Since it's given that two forces acting on each other have a magnitude 5N each and they have an angle of 120° between them.

Let us assume

F=5N

Let the angle between them be called x.

So, x =120°

$\sqrt{f {}^{2} + f {}^{2} + 2f {}^{2} \cos( x ) } = resultant$

On applying this formulae we get,

Resultant = R = (√(5^2 +5^2 + 2×5^2 cos 120°))

R = √(25+25+2*25*(-1/2) = √(50-25)

= √25 = 5N

So the resultant of these two forces acting at 120° has a magnitude of 5N .

Hence, the required answer is 5N.