Complex sentence: The first is a lever used to apply the torque to the fastener being tightened and serves also as the handle of the tool, when force is applied to this beam it will deflect predictably and proportionally with said force in accordance with Hooke's law.
Split into simpler sentences: The first is a lever used to apply the torque to the fastener being tightened and serves also as the handle of the tool. When force is applied to the handle it will deflect predictably and proportionally with said force in accordance with Hooke's law.