Kinematics and Kinetics Practice Test 2026 – Complete Human Movement Exam Prep

The key idea is how a lever is organized around its pivot (the axis). In a first-class lever, the pivot sits between the force you apply (effort) and the load you’re moving (resistance). This arrangement means the two sides of the lever rotate about the same central point, so you’re creating torques on opposite sides of the pivot. Whether you gain a mechanical advantage or not depends on how far the effort is from the pivot compared with how far the resistance is. A classic example is a seesaw: the fulcrum is in the middle, with effort on one side and a load on the other, balanced around that central axis.

That’s why the description where the axis lies between effort and resistance is the correct one for a first-class lever. If the axis were not between them, you’d be describing a different lever class, and if the statement claimed there is no axis movement, that would not fit the lever concept at all.

In short, first-class levers are defined by a pivot located between the input force and the load, allowing the system to balance or magnify effort depending on arm lengths.