Final answer:
Torque about an axis can be calculated using the equation T = rF sin θ, which incorporates the distance from the pivot point to the point of force application, the magnitude of the force, and the sine of the angle between them.
Step-by-step explanation:
The torque τ about a given axis due to a force vector τd can be calculated if we know the distance r from a pivot point to where the force is applied, the magnitude of the force F, and the angle θ between the force and a vector from the point of application to the pivot point. The equation to calculate torque is T = rF sin θ, where T represents torque and r1 is the perpendicular lever arm, defined as r1 = r sin θ. To find the torque of the force τd about axis d, we must use the distance d and angle ϕ mentioned in the problem, combined with the magnitude of the force, and the appropriate angles between the force and its lever arm.