A ball is thrown vertically upward from the surface of the earth. Consider the following quantities: (1) the speed of the ball; (2) the velocity of the ball; (3) the acceleration of the ball. Which of these is (are) zero when the ball has reached the maximum height? 1 only 1 and 3 only 1 and 2 only 1, 2, and 3 2 only
Answer
Quantities That Become Zero at Maximum Height in Vertical Motion
When a ball is thrown vertically upward from the surface of the Earth, it moves upward, slows down due to gravity, reaches a maximum height, and then falls back downward. Understanding what happens at the maximum height is key to answering this question accurately.
📌 Definitions of the Quantities Involved
- (1) Speed: The magnitude of velocity. Always non-negative.
- (2) Velocity: A vector quantity with magnitude and direction. Positive when upward, negative when downward.
- (3) Acceleration: In vertical motion, this is due to gravity and directed downward, with a constant value of 9.8 m/s².
⏫ What Happens at Maximum Height?
At maximum height:
- 👉 The velocity becomes zero, because the object stops momentarily before reversing direction.
- 👉 The speed, being the magnitude of velocity, is also zero.
- 👉 The acceleration is not zero; gravity continues to act with 9.8 m/s² downward.
✅ Correct Analysis
At the highest point:
- Speed = 0 ✅
- Velocity = 0 ✅
- Acceleration ≠ 0 ❌ (still 9.8 m/s² downward)
🎯 Final Answer
📘 Summary Table
| Quantity | At Maximum Height |
|---|---|
| Speed | Zero ✅ |
| Velocity | Zero ✅ |
| Acceleration | 9.8 m/s² downward ❌ |
🧠 Conclusion
At the peak of vertical motion, both speed and velocity become zero momentarily, but acceleration remains constant due to Earth’s gravitational pull.
Quantities That Become Zero at Maximum Height in Vertical Motion
When a ball is thrown vertically upward from the surface of the Earth, it moves upward, slows down due to gravity, reaches a maximum height, and then falls back downward. Understanding what happens at the maximum height is key to answering this question accurately.
📌 Definitions of the Quantities Involved
- (1) Speed: The magnitude of velocity. Always non-negative.
- (2) Velocity: A vector quantity with magnitude and direction. Positive when upward, negative when downward.
- (3) Acceleration: In vertical motion, this is due to gravity and directed downward, with a constant value of 9.8 m/s².
⏫ What Happens at Maximum Height?
At maximum height:
- 👉 The velocity becomes zero, because the object stops momentarily before reversing direction.
- 👉 The speed, being the magnitude of velocity, is also zero.
- 👉 The acceleration is not zero; gravity continues to act with 9.8 m/s² downward.
✅ Correct Analysis
At the highest point:
- Speed = 0 ✅
- Velocity = 0 ✅
- Acceleration ≠ 0 ❌ (still 9.8 m/s² downward)
🎯 Final Answer
📘 Summary Table
| Quantity | At Maximum Height |
|---|---|
| Speed | Zero ✅ |
| Velocity | Zero ✅ |
| Acceleration | 9.8 m/s² downward ❌ |
🧠 Conclusion
At the peak of vertical motion, both speed and velocity become zero momentarily, but acceleration remains constant due to Earth’s gravitational pull.