The lead screw (also called a power screw or a jack screw) is used to convert the rotation of a motor shaft into a translational motion of the mass m (see Figure). For one revolution of the screw, the mass translates a distance L (called the screw lead). As felt on the motor shaft, the translating mass appears as an equivalent inertia. Use kinetic energy equivalence to derive an expression for the equivalent inertia. Let IS be the inertia of the screw.

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