Question

Four forces are acting on a body. if the body doesn't change its position or shape, the forces:
A. Must be of equal magnitude
B. Must be parallel & opposite
C. Must add up to zero when taken as vectors
D. Must be in a single line and in same direction

Answer 1

The above problem is based on the equilibrium of forces, acting on a specific object. When it is observed that the object is not moving on the application of forces, then, in this case, one can say that it is in equilibrium state or merely that the net force acting on the object appears to be zero. And this is to be analysed numerically if the sum of all the forces acting on the object comes out to be zero or null.

Complete step by step solution:
When a body is considered by application of force, such that there is no change in the shape and no change in the position of the body, then is the condition for the equilibrium of forces. The vectors of forces in this condition are acting in the specific direction and contribute the total sum as zero.

Therefore, if the body doesn't change its position or shape, they must add up to zero when taken as vectors, and option (C) is correct.

Note: Try to understand the meaning of the equilibrium of forces. The equilibrium of forces makes any sense when the resultant value of force appears to be as zero. Analysing any such condition makes sure that you are getting the exact sum of forces as a null value. The equilibrium of forces has several applications in balancing as well as in the applied physics. Moreover, in balancing the machine elements, this concept is widely used to make sure the smooth performance of the machine elements.