Sure! Let’s break it down into **two steps**: --- ## **Step 1: Identify All Forces Acting on the Block** ### **Forces Present:** - **Weight (\( W \))**: Acts downward (through the center of gravity) - **Normal Force (\( N \))**: Perpendicular to the inclined rail - **Friction Force (\( F_f \))**: Opposes impending motion (up the rail) - **Applied Forces (\( P_1 \) and \( P_2 \))**: As shown, with given directions and angles ### **Explanation:** At the instant the block starts to move up the rail, friction acts **down the rail** (opposing the impending upward motion). The free-body diagram should show: - The **weight** acting vertically down. - The **normal force** perpendicular to the rail. - The **friction force** down the rail. - The **applied forces** \( P_1 \) (at angle \( \theta \)) and \( P_2 \) (straight down). --- ## **Step 2: Draw the Free-Body Diagram** ### **Diagram Features:** - Draw the block on the inclined rail (show the 35° angle). - Mark the following arrows: - \( W \) (downward) - \( N \) (perpendicular to rail) - \( F_f \) (down the rail) - \( P_1 \) (at angle \( \theta \) to the rail) - \( P_2 = 140\,\text{N} \) (straight down) #### **Explanation:** This diagram helps visualize all the forces acting on the block as it just starts to move up the rail. The direction of friction is crucial—it is always **opposite to the direction of impending motion**. --- ## **Final Answer:** **The free-body diagram of the block when the block starts to move up the rail is:** - Block on the 35° inclined rail - Weight (\( W \)) acting vertically downward - Normal force (\( N \)) perpendicular to the rail - Friction force (\( F_f \)) acting down the rail - \( P_1 \) acting at angle \( \theta \) relative to the block - \( P_2 = 140\,\text{N} \) acting vertically downward **(Label all forces clearly as described above.)** --- **Summary:** **Step 1:** Identify and label all forces. **Step 2:** Draw the block, rail, and all forces with correct directions, especially friction (down the rail).