Motion/Acceleration: free-fall gravity vs. ball being push downward

In summary: It will continue to decrease as it moves downward, but the instant the person lets go of it, its acceleration is equal to g.In summary, when a ball is given an initial downward push instead of being freely released, the resulting acceleration due to gravity, or 'g', will be different. While a freely released ball will experience a constant acceleration of 9.8 m/s2, a ball that is pushed downward will have an additional acceleration due to the initial force applied. However, this acceleration will eventually decrease and the ball will be acted upon by gravity alone, resulting in a final acceleration of 9.8 m/s2 by the time it hits the ground. The question of whether the gravitational acceleration, 'g', depends on
  • #1
nixm01
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Motion/Acceleration: free-fall gravity vs. ball being "push" downward

Homework Statement


If by accident a ball were given an initial downward push instead of being freely released, would the resulting g be different? Explain.
(this is ignoring any air resistance)


Homework Equations


N/A

The Attempt at a Solution


Being freely released, gravity is the only factor being considered so the acceleration being consistently acted upon it is 9.8 m/s2. But if being pushed downward, the ball would now have even more acceleration from the extra "force", correct? so there would definitely be a different resulting g between the two.

Is my wording correct? In my first Physics class and am not too comfortable with the lingo yet. I am also a little confused on what 'g' is actually referring to. Is 'g' referring to gravity or just acceleration in-general? Because if meaning acceleration, then I would assume what I said is correct above. Any assistance in helping me correctly conceptualize this information?

Thanks guys!
nixm01
 
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  • #2


'g' specifically means the gravitational acceleration of an object at the surface of the Earth, 9.80m/s^2. A general acceleration is simply denoted 'a'.

I believe the problem implies that the force does not act on the object constantly. All it says is that at the start, it's thrown downward. So imagine someone at the top of a skyscraper with a ball. He throws it downward. The force from the person acts just for the fraction of a second to give it an initial velocity downward. The problem seems to be asking what happens after the ball has been released. So in short, the problem is basically asking if the gravitational acceleration, g, depends on the initial velocity.
 
  • #3


Thank you for the reply.

I would assume yes that it would have an affect on the resulting 'g' because it was given that extra acceleration down - I guess as a boost. Am I correct in assuming that any extra acceleration given to an object will no longer be acted upon by gravity alone, thus resulting in a higher 'g'?

That seems to be the most obvious assumption, but I am not sure if there is another "law" that states other-wise. To my surprise, the study of motion/acceleration/gravity has actually thrown a few curve balls at me with things I would have never thought about/known.
 
  • #4


Another thought I am having is wondering if the question is needing answer describing what you stated - that although the beginning acceleration will be higher due to the push, it will eventually go back to being only acted upon by gravity by the time it hits the ground - which seams plausible. BUT, wouldn't that depend on how high up the ball is from the ground? Because if the above assumption is true and it will eventually get back to 9.8 m/s2, if I am just throwing the ball down from a standing position, by the time the ball hit the ground, the resulting g would still be higher since it had not had any time to change (again, only if I was correct in my assumption).

Thanks guys
 
  • #5


nixm01 said:
Another thought I am having is wondering if the question is needing answer describing what you stated - that although the beginning acceleration will be higher due to the push, it will eventually go back to being only acted upon by gravity by the time it hits the ground - which seams plausible. BUT, wouldn't that depend on how high up the ball is from the ground? Because if the above assumption is true and it will eventually get back to 9.8 m/s2, if I am just throwing the ball down from a standing position, by the time the ball hit the ground, the resulting g would still be higher since it had not had any time to change (again, only if I was correct in my assumption).

Thanks guys

No. The instant the ball leaves the persons hand, the acceleration becomes g = 9.80m/s^2.
 

Related to Motion/Acceleration: free-fall gravity vs. ball being push downward

1. What is free-fall gravity?

Free-fall gravity is the acceleration due to the Earth's gravitational force acting on an object. It is the same for all objects regardless of their mass and is equal to 9.8 meters per second squared (m/s^2) near the Earth's surface.

2. How does free-fall gravity differ from other types of acceleration?

Unlike other types of acceleration, free-fall gravity is a constant acceleration that is always directed towards the center of the Earth and does not depend on the object's mass or shape.

3. What happens to an object during free-fall?

When an object is in free-fall, it is experiencing a state of weightlessness as it is only being affected by the Earth's gravitational force. This means that the object will continue to accelerate towards the ground until it reaches terminal velocity or is stopped by another force.

4. How does pushing a ball downward affect its motion compared to free-fall gravity?

Pushing a ball downward introduces an external force that acts against the force of gravity. This will cause the ball to experience a different type of acceleration, depending on the strength and direction of the push. It may also cause the ball to deviate from its natural free-fall path.

5. How can we calculate the acceleration of an object in free-fall?

The acceleration of an object in free-fall can be calculated using the equation a = g, where a is the acceleration and g is the acceleration due to gravity. Alternatively, it can also be calculated using the equation a = (v^2 - u^2)/2s, where v is the final velocity, u is the initial velocity, and s is the distance traveled.

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