Question

Three forces of magnitude 6 N, 6 N and √72 N  act as a corner of a cube along three sides as shown in fig. Resultant of these forces is

1. 12 N along OB
2. 18 N along OA
3. 18 N along OC
4. 12 N along OE

Answer 1

Correct Answer: 4. 12 N along OE

Explanation :

Let sides OC, OG and OA represent x,y and z respectively.

Resultant of forces = 6i + √72 j + 6j = vector R

R = √(36 + 72 + 36) = √144 = 12 N

Resultant of OA and OC is along OB and of magnitude √72

( ∵ they are perpendicular)

∴ Resultant of OC, OG and OA is same as OB √72 + OG √72

Its resultant will be along OE.