Question

$ABCD$ is a quadrilateral. Forces $\overrightarrow{BA},\overrightarrow{BC},\overrightarrow{CD}$ and $\overrightarrow{DA}$ act at a point. Their resultant is:

• A. $2\overrightarrow{AB}$
• B. $2\overrightarrow{DA}$
• C. Zero vector
• D. $2\overrightarrow{BA}$

Answer 1

The correct option is D $2\overrightarrow{BA}$

As $AB,BC,CD,DA$ form a quadrilateral $\Rightarrow$

$AB+CD+BC+DA=0$

and $AB=-BA$

so $BA=BC+CD+DA$

Resultant fra.$=F_2=BA+BC+CD+DA$

$=BA+BA$

$F_r=2BA$