The balance beam stays horizontal due to the principle of torque, which is the tendency of a force to rotate an object around an axis. In the case of the balance beam, the weight on either side of the fulcrum creates equal and opposite torques, keeping the beam in a state of equilibrium.
The balance of the beam can be affected by factors such as the weight of the beam itself, the position of the fulcrum, and the distance and weight of the objects placed on either side of the fulcrum. These factors can alter the torques acting on the beam and cause it to tilt.
The fulcrum is placed in the center of the beam to ensure equal torques acting on either side, resulting in a balanced and horizontal beam. Placing the fulcrum off-center would create an imbalance and cause the beam to tilt towards the heavier side.
In theory, the balance beam can be perfectly horizontal if the weights on either side of the fulcrum are exactly equal. However, in real-life scenarios, it is nearly impossible to achieve perfect balance due to factors such as friction and imperfections in the beam itself.
The balance beam is used in a variety of real-world applications, such as in construction to lift and move heavy objects, in weighing scales to measure weight, and in gymnastics as a piece of equipment for balancing and performing acrobatic routines. It is also used in physics experiments to demonstrate principles of torque and equilibrium.