Question

Imagine you throw a tennis ball vertically into the air. At the exact top of its trajectory it is at rest. What is the magnitude of its acceleration at this point? a. 9.8 m/s2.b. -9.8 m/s2.c. 0.d. other(specify).

Answer 1

Answer:

a) 9.8 m/s²

Explanation:

• At any point during its trajectory, the only influence on the ball is due to gravity, so the ball  is always accelerated by it.
• This is true even if the ball momentarily stops, like when it reaches to its maximum height before starting to fall down.
• Close to the surface of  the Earth, the magnitude of this acceleration is 9.8 m/s², as the magnitude is always a positive quantity, so the right answer is a).