解答上述试题---**15. (2023·眉山)**
**Question Stem:**
学校组织学生参加劳动实践活动，在基地发现了一台活塞式抽水机，在杠杆C处用力便可取水。请在图中画出:
(School organized students to participate in labor practice activities, and found a piston pump at the base. Water can be drawn by applying force at lever point C. Please draw in the figure:)
**Sub-questions:**
(1) 阻力F₂的力臂L₂; (The force arm L₂ of resistance F₂;)
(2) 在C处所用最小力F₁的示意图。(Schematic diagram of the minimum force F₁ applied at point C.)
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**Chart/Diagram Description:**
* **Type:** Schematic diagram of a piston pump connected to a lever mechanism.
* **Main Elements:**
* **Piston Pump:**
* A vertical cylindrical body, with the lower section colored blue indicating water.
* Two internal sections labeled **A** (upper) and **B** (lower).
* A bell-shaped piston is located in section A, connected to the lever mechanism above.
* A horizontal **出水管** (Water outlet pipe) extends from the upper part of the pump to the left.
* A vertical pipe extends downwards from section B, with **大气压** (Atmospheric pressure) labeled on both its left and right sides, indicating external atmospheric pressure.
* A downward-pointing force vector, labeled **F₂**, is shown acting on the piston's connecting rod, originating from the connection point to the lever.
* **Lever Mechanism:**
* A pivot point, labeled **O**, is located on the right side of the pump's upper structure.
* A curved lever arm extends from point O to the right and downwards. The end of this lever arm is the point C (implied by the question, where force F₁ is applied).
* **Drawn Elements (Answers to Sub-questions):**
* **(1) Force Arm L₂ of Resistance F₂:**
* A dashed horizontal line segment, labeled **L₂**, is drawn from the pivot point O to the vertical line of action of force F₂.
* A right-angle symbol is placed at the intersection of L₂ and the line of action of F₂, indicating that L₂ is the perpendicular distance (force arm).
* **(2) Schematic Diagram of Minimum Force F₁ at Point C:**
* A force vector, labeled **F₁**, is drawn at the end of the lever (point C).
* The vector points diagonally upwards and to the left, approximately perpendicular to the lever arm at point C. This direction typically represents the minimum force required for rotation.
* A curved dashed line segment, labeled **L₁**, is shown extending from the pivot point O to the point of application of F₁ (point C), representing the length of the effort arm.