Understanding Acceleration and Velocity in Relation to Gravitational Force

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Discussion Overview

The discussion revolves around the relationship between acceleration, velocity, and gravitational force, particularly in the context of moving an object upwards at a constant velocity. Participants explore the conditions necessary for maintaining constant velocity against gravitational forces, including the implications of applied force and weight.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether it is possible to move upwards with a constant velocity of 5 m/s using a constant force, expressing uncertainty about their understanding.
  • Another participant states that for an object to move with constant velocity, the net force must be zero, which requires an upward force equal to the weight of the object (20 N) once the desired velocity is reached.
  • A different contribution suggests that if the object is dragged with a constant force that perfectly balances friction, it could maintain a constant velocity without vertical movement.
  • Another participant emphasizes that the force needed to maintain constant upward velocity is equal to the object's weight.
  • One participant introduces the idea that gravitational force decreases with distance from the Earth's surface, suggesting that even if initial forces are ignored, there would still be an increasing acceleration as one moves further away from Earth.

Areas of Agreement / Disagreement

Participants express differing views on the conditions for maintaining constant velocity in the presence of gravitational force. While some agree on the necessity of balancing forces, others introduce complications related to distance from Earth and gravitational changes, indicating that the discussion remains unresolved.

Contextual Notes

There are assumptions regarding the constancy of gravitational force and the effects of friction that are not fully explored. The discussion also does not resolve the implications of changing gravitational force with altitude.

cb767
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I can't believe I don't remember this. Is it possible to move upwards with a constant velocity? For example, if a block weighs 20 Newtons, and I want it to go at a constant velocity of 5 m/s , could I do that with a constant force? For some reason I don't think I can, but maybe I'm just screwing myself up somewhere...
 
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Force= mass times acceleration. In order that something move with constant velocity it is necessary that the acceleration be 0 and so that the net force be 0. If an object weight 20 N. that means that there is a force of 20 Newtons downward. To balance that and get a net force of 0, you need an upward force of 20 N also. Notice that the "5 m/s" doesn't come into that. In order to move an object weighing 20 N upward at 5 m/s you must first apply a force greater than 20 N upward so there is an acceleration upward. When the speed gets to 5 m/s then you must reduce the upward force to exactly 20 N to keep that constant speed.
 
Incidentally,your case would work out fine,if you were to drag the body with a constant force which would balance the friction force perfectly (i.e.no vertical movement).

Daniel.
 
The amount of force needed to move upwards at constant velocity is the weight of the object.
 
as u go further away from the Earth surface the gravitaional force will continously reduce .so even if u were to ignore the intial extra force applied there would still be an accelleration whose rate would increase the further u went from the earth
 

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