Can a Ball or Bullet Accelerate After Being Released?

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Discussion Overview

The discussion centers around whether a ball or bullet can accelerate after being released from a pitcher's hand or a gun. Participants explore the implications of forces acting on the objects post-release, considering factors like gravity, air resistance, and other forces that may influence motion.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant asserts that once the force from the pitcher or the explosion in the gun ceases, the ball or bullet will not accelerate further and will begin to slow down due to drag and gravity.
  • Another participant argues that the bullet will still experience acceleration due to gravity, air resistance, and the Coriolis effect, suggesting that these forces contribute to its motion after being fired.
  • A question is raised about whether the bullet accelerates towards the target after leaving the gun, with one participant stating that it does not gain speed towards the target after release.
  • Concerns are expressed regarding the belief that the bullet continues to accelerate for a distance after leaving the barrel, with a request for scientific explanation to clarify this point.
  • One participant mentions the Magnus effect, stating that a thrown ball experiences additional acceleration due to its spin, although this does not increase its forward velocity.
  • Another participant emphasizes Newton's 2nd Law, stating that without a force, there can be no acceleration, and challenges the idea that gases continue to push the bullet after it has traveled a significant distance.

Areas of Agreement / Disagreement

Participants express differing views on whether a ball or bullet can accelerate after being released, with some asserting that they cannot while others argue that various forces can lead to acceleration in different contexts. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference various forces and effects, such as gravity, air resistance, and the Magnus effect, but there is no consensus on the implications of these forces on the acceleration of the objects in question.

ratmeister
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Hi, please help me settle a bet...

When a pitcher throws a ball, can the ball accelerate after it leaves the pitchers hand? Same question with a bullet and a gun...

I say that once the force of either the pitcher or the explosion of the gas in the gun stops, the ball or bullet won't accelerate any more but will start slowing down as drag and gravity start taking affect...

Is that line of thought correct?
Can someone please give me the science behind the answer?

I am a physics amature with a lot of discovery and science channel knowledge but no formal physics education and any help to prove an answer would be appreciated. Thanks
 
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Let's take the bullet as the example.

1) The bullet will accelerate towards the centre of the Earth due to gravity.
2) The bullet will deccelerate due to air resistance, this is effectively the same thing as acceleration.
3) The bullet will accelerate due to the Coriolis effect (unless the bullet is fired along the equator).

In short, YES, the bullet will accelerate.
 
But will the bullet accelerate towards the target in perspective to the shooter in an example of a shooting range? I mean, will it go faster towards the target once it leaves the gun?
 
ratmeister said:
But will the bullet accelerate towards the target in perspective to the shooter in an example of a shooting range? I mean, will it go faster towards the target once it leaves the gun?
No. Your thinking is correct. (The myth is that the bullet keeps gaining speed for a while after it leaves the gun. Nope. Same for the tossed ball.)
 
Can you please explain why? When I told him my thoughts, he said that he just "knows" that the object accelerates after the initial force stops. I agreed that with a gun, the expansion of gasses might still push the bullet a bit after it leaves the barrel, and his thought was that the bullet accelerates for a few hundred feet. Any scientific explanation would be appreciated. Thanks
 
Acceleration requires a force. Ask your friend what provides the force. (Does he really think the gases still push the bullet after hundreds of feet? :rolleyes:) For the thrown ball, obviously the hand exerts a contact force against the ball--lose that contact, the force is gone.
 
There actually is some additional acceleration a thrown ball experiences after leaving the pitcher's hand...it's known as the http://en.wikipedia.org/wiki/Magnus_force" and is due to the ball's spin. However, it cannot add any forward velocity to the ball, it can only exert a force tangential to the oncoming air.
 
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Does anyone have any science to back this theory up?
 
ratmeister said:
Does anyone have any science to back this theory up?

Er.. it's called Newton's 2nd Law! F=ma! If there's no force, there's no acceleration. It is that simple.

Any intro physics text will have that.

Zz.
 

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