What Is the Connection Between Force and Acceleration?

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Discussion Overview

The discussion revolves around the relationship between force and acceleration, exploring concepts from Newton's laws of motion. Participants express confusion regarding the conditions under which objects accelerate and the role of friction in this relationship.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that a force applied to an object results in acceleration but questions why this occurs, suggesting that the force required to start moving an object is greater than that needed to maintain its motion.
  • Another participant states that as long as there is a net force on an object, it will accelerate.
  • A different participant adds that if a constant force is maintained while friction increases with velocity, eventually the friction force will equal the applied force, resulting in zero net force and no acceleration.
  • There is a question regarding the definition of net force, with a participant seeking clarification on whether it refers to a force greater than the initial force needed to start moving the object.
  • A later reply clarifies that the net force is the vector sum of all forces acting on the object, emphasizing that a non-zero net force is necessary for acceleration, while zero net force results in no acceleration.
  • It is mentioned that once an object is in motion, it does not require a net force to keep moving unless opposing forces like friction are present, which must be overcome to maintain motion.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the concepts of force and acceleration, with some agreeing on the necessity of net force for acceleration, while others raise questions about the implications of friction and net force definitions. The discussion remains unresolved with multiple competing views present.

Contextual Notes

Participants reference Newton's laws but do not fully resolve the implications of friction and net force in different scenarios, leaving some assumptions and definitions open to interpretation.

jamesabc
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i was just wondering about the relationship between force and acceleration.

from what i have learned in school and at university is that when a force is applied to an object, the object is accelerated. But what i am a bit confused about is why objects accelerate.

this is what i think but am not sure if it is right. it takes a certain amount of force to start an object moving, but as soon as the object starts moving the force required to keep it moving is less than the force to get to start moving in the first place. so if the initial force is keep constant then there will be acceleration? but eventually the friction from air resistance or whatever will eventually work against the acceleration and acceleration will be zero.

is this right?
 
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As long as there is a net force on an object, it will accelerate.
 
But if you maintain a constant force and friction increases with velocity, eventually the friction force will be equal to the applied force so the net[\b] force will be 0 and there will no longer be any acceleration.
 
Doc Al said:
As long as there is a net force on an object, it will accelerate.

by net force do you mean force greater than the force to get the object moving? or something else?
 
jamesabc said:
by net force do you mean force greater than the force to get the object moving? or something else?
The net force on an object is the vector sum of all individual forces acting on the object. As long as that net force is non-zero, the object will accelerate. When the net force is zero, the acceleration is zero. (Newton's 2nd law.)

To start something moving (from rest) some kind of force is needed. Once that force is removed, or other forces (like friction) are added, such that the net force is zero, the object will continue moving in a straight line at constant speed. (Newton's 1st law.)

In other words: You need a net force to change an object's motion (get it moving, for example); but once it's moving, it does not require a net force to keep moving. Of course, if friction acts on the moving object, you need to keep pushing to maintain the motion. But your push merely acts to overcome friction, making the net force zero.
 

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