Final answer:
To calculate the moment about point O due to cable BC's tension on a boom, use the cross product of the position vector from O to C and the tension in BC.
Step-by-step explanation:
The question relates to determining the moment about a point due to tension in a cable, which is a fundamental concept in statics, a branch of Engineering mechanics. To determine the moment about point O due to the force of cable BC on the boom, one would use the equation M = r × T, where M is the moment, r is the position vector from the point of rotation (point O) to the point where the force is applied, and T is the tension in the cable. Assuming point O is at the base of the boom and the cable applies a force at point C, the magnitude of the moment will be the product of the distance from O to C (which can be measured along the boom if the cable is perpendicular to it) and the tension in cable BC.