Learn about applications of y = ax² in daily life, such as the distance an object falls.
📘 Example ①
When an object is dropped from a height, its falling distance d m after t seconds is represented by d = 5t². Find the falling distances after 2 seconds and 4 seconds.
Answer:d = 5×4 = 20m (after 2 seconds), d = 5×16 = 80m (after 4 seconds)
When an object is dropped from a height, its falling distance d m after t seconds is represented by d = 5t². Find the falling distances after 2 seconds and 4 seconds.
Answer:d = 5×4 = 20m (after 2 seconds), d = 5×16 = 80m (after 4 seconds)
💡 Key Point
- d = 5t² (free fall) is a practical example of y = ax²
- When t doubles, d becomes four times as large
Practice Problems
- For d = 5t², after how many seconds will the falling distance be 45m?
Answer and Explanation
- Answer:After 3 seconds. 5t²=45 → t²=9 → t=3 (positive).