How is mechanical advantage in a lever system calculated?

How is mechanical advantage in a lever system calculated?

• A. MA = length of effort arm / length of load arm
• B. MA = length of load arm / length of effort arm
• C. MA = sum of the arms
• D. MA = force / velocity

Answer: (B)

The key idea is that a lever changes force into distance through balance of torques. For an ideal lever, the effort force times its distance from the fulcrum equals the load force times its distance from the fulcrum: F_effort × d_effort = F_load × d_load. From this, you get relationships between forces and distances. In many PE courses, mechanical advantage is defined using the distance ratio of the two arms: MA = d_load / d_effort. This means the lever’s advantage is determined by how the load arm length compares to the effort arm length. If the load arm is longer relative to the effort arm, the ratio increases, which is the convention used in this item.

The key idea is that a lever changes force into distance through balance of torques. For an ideal lever, the effort force times its distance from the fulcrum equals the load force times its distance from the fulcrum: F_effort × d_effort = F_load × d_load. From this, you get relationships between forces and distances. In many PE courses, mechanical advantage is defined using the distance ratio of the two arms: MA = d_load / d_effort. This means the lever’s advantage is determined by how the load arm length compares to the effort arm length. If the load arm is longer relative to the effort arm, the ratio increases, which is the convention used in this item.