Final answer:
The net torque is the sum of individual torques, calculated with the formula t = rFsin(θ), considering the forces' magnitudes, distances from the axis, and the angles at which they are applied.
Step-by-step explanation:
The net torque on a bar can be calculated by summing the individual torques created by forces acting on the bar, relative to a specific axis. In this case, we calculate the torque exerted by a force using the formula t = rFsin(θ), where r is the distance from the axis to the point of application of the force, F is the magnitude of the force, and θ is the angle between the force vector and the lever arm. If the given force is 40 N and is acting perpendicular to the door at a distance of 0.800 m, the torque would be calculated as t = 0.800 m x 40 N x sin(90°) or 32 N·m. Assuming negligible opposing friction and that all forces are exerted at right angles to the rotation axis, the net torque is simply the sum of these individual torques, with each torque having a positive or negative sign depending on the direction of their rotational effect around the axis.