Three forces act on a body. Two of them are 5î – 4ĵ N and 3î – 7ĵ. What is the value of the other force for body to be in equilibrium ?
Answer & explanation
Correct answer: option 4
For the body to be in equilibrium, the sum of all the forces acting on it must be $zero$.
Let the unknow force by $F$.
Equilibrium condition : $5 \hat{i} - 4\hat{j} - [3\hat{i} - 7\hat{j}] + F = 0$
$\Rightarrow F = -2\hat{i} - 3\hat{j}$