Why Is the Acceleration Not Zero at the Highest Point of a Thrown Baseball?

[demonelite123]

A baseball is thrown upwards. What is the acceleration at the highest point?

i thought the acceleration would be 0 since velocity at the highest point is 0 and the derivative of velocity is acceleration. Since velocity is not changing, shouldn't acceleration be 0?

However the answer is supposed to be 9.8 m/s^2 downwards. why is the answer the acceleration of gravity and not 0?

 

[LowlyPion]

A baseball is thrown upwards. What is the acceleration at the highest point?

i thought the acceleration would be 0 since velocity at the highest point is 0 and the derivative of velocity is acceleration. Since velocity is not changing, shouldn't acceleration be 0?

However the answer is supposed to be 9.8 m/s^2 downwards. why is the answer the acceleration of gravity and not 0?

Velocity at the top is 0. But the rate of change is still 9.8 m/s² until it hits something, right?

 

[nlightner]

The acceleration at the highest point of a thrown baseball is indeed 0, as you correctly stated. This is because at the highest point, the velocity of the baseball is momentarily 0 and therefore there is no change in velocity, resulting in an acceleration of 0.

However, the 9.8 m/s^2 value that is often associated with the acceleration at the highest point is the acceleration due to gravity, which is a constant force acting on all objects near the Earth's surface. This acceleration is always present, regardless of the object's velocity or position.

In the case of the baseball, even though its velocity is momentarily 0 at the highest point, the acceleration due to gravity is still acting on it, pulling it downwards towards the Earth at a rate of 9.8 m/s^2. This is why the answer is not 0, but rather the acceleration of gravity.

It is important to note that this acceleration only applies at the highest point, as the baseball is in free fall and not being influenced by any other external forces. Once it starts to descend, the acceleration due to gravity will cause its velocity to increase, resulting in a non-zero acceleration.

In summary, while the acceleration at the highest point is 0, the acceleration due to gravity is still acting on the baseball and remains a constant force throughout its entire trajectory.