Final answer:
Net torque is calculated by summing up individual torques from all applied forces, which is the product of each force, the distance from the pivot point, and the sine of the angle between the force and lever arm. The center of mass simplifies torque calculations when used as the pivot. Counterclockwise torques are positive, and clockwise torques are negative.
Step-by-step explanation:
To calculate the net torque on a beam, you need to consider each force's contribution to the rotational motion around a pivot point. When examining torques around, for instance, the center of mass (CM) of a beam, you apply the concept of torque (τ), which is the product of the force (F), the distance (lever arm, r) from the pivot point to the point where the force is applied, and the sine of the angle (θ) between the force and the lever arm. The formula for torque is τ = F × r × sin(θ). The counterclockwise torque is considered positive, and the clockwise torque is negative. Additionally, the net torque is the sum of all individual torques.
In a situation with multiple forces, like on a flywheel or a beam with weights, you treat each force separately, calculate its torque, and then sum them, taking into account their directions to determine the overall net torque. In the case of a beam, if it has uniform mass distribution, the center of mass is typically at its midpoint, which simplifies the torque calculations when using it as the pivot point. Remember that when a force is directly perpendicular to the lever arm, the angle is 90°, and the sine of 90° is 1, making the torque calculation a straightforward multiplication of force and distance.