Story #5: A car changes its position from 52km [W] to 139 km [E]. What is the car's displacement?

The car's displacement is **191 km [E]**.<br /><br />Here's how to calculate it:<br /><br />1. **Understand Displacement:** Displacement is a vector quantity that represents the change in position. It has both magnitude (how far the object moved) and direction.<br /><br />2. **Establish Directions:** West is typically considered negative and East is positive.<br /><br />3. **Calculate the Change:** The car starts at -52 km (West) and ends at +139 km (East). The change in position is the final position minus the initial position:<br /><br /> 139 km - (-52 km) = 139 km + 52 km = 191 km<br /><br />4. **Determine the Direction:** Since the result is positive, the displacement is in the East direction.<br /><br />Therefore, the car's displacement is $\boxed{191 \text{ km [E]}}$.<br />