Final answer:
The resultant force will be greatest when two forces acting on a body are at a 90° angle to each other, as this produces the maximum torque with sin(90°) = 1 and the largest resultant net force.
Step-by-step explanation:
When two forces act concurrently on a body, the resultant force will be greatest when the angle between them is 90° (a right angle). This is because the sine of 90° is 1, which is the maximum value sine can have, making sin(90°) = 1 in the torque equation T = FR sin θ.
When calculating the net force of two perpendicular forces using the Pythagorean theorem, the forces combine to form the largest resultant.