Ok so my teacher has recently covered this chapter, but one of the

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Discussion Overview

The discussion revolves around the concept of forces acting on an object, specifically addressing the conditions under which an object experiences zero acceleration and moves at constant velocity. Participants explore the implications of balanced forces, the role of friction, and the energy required to maintain motion, touching on Newton's laws and the nature of work done on an object.

Discussion Character

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

Main Points Raised

  • One participant notes that for an object to experience zero acceleration, the forces acting on it must be balanced, questioning how an object can maintain constant velocity without a net force.
  • Another participant explains that an object in motion will continue at constant velocity until acted upon by another force, emphasizing that work is done to overcome friction when moving at constant speed.
  • It is mentioned that when an object moves at constant speed, its kinetic energy remains constant, and no net work is done on it unless it is accelerated or decelerated.
  • A participant raises a question about why a car engine must continue to burn fuel at constant speed, attributing this to the friction that resists motion, requiring additional force to maintain speed.
  • Some participants clarify that work must be done to overcome friction, which converts energy into heat, and that the applied force remains on the object, countered by friction.
  • There is a discussion about whether the object does work on other objects or only on itself, with some uncertainty expressed regarding the nature of work in this context.

Areas of Agreement / Disagreement

Participants express varying views on the nature of work and energy in relation to constant velocity and friction. While some points are clarified, there remains no consensus on all aspects of the discussion, particularly regarding the implications of forces and work.

Contextual Notes

Some participants highlight the distinction between mechanical energy and other forms of energy, such as heat, when discussing work done against friction. There are also unresolved questions about the relationship between applied forces and resultant forces in dynamic equilibrium.

Who May Find This Useful

This discussion may be useful for students and individuals interested in understanding the principles of dynamics, particularly those grappling with concepts of force, motion, and energy in physics.

  • #31


But harrylin, in this case I assuming the applied force and frictional force to be equal in magnitude .
 
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  • #32


Celluhh said:
But harrylin, in this case I assuming the applied force and frictional force to be equal in magnitude .
Exactly-that's my equation 3. When your car creates a friction force equal in magnitude to its driving force, then its speed will be constant.
 
  • #33


Yeah I know, but why is it so? Basically what I'm asking is where does the car get the kinetic energy from to keep it moving at constant speed ? The kinetic energy it has from the constant applie force had already been used to deal with the equal in magnitude constant friction force , so where does the extra energy come from ?
 
  • #34


Oh and to deviate a little, on a stairxase, which is the point at which a person has the most kinetic energy?
 
  • #35


@sophiecentaur, what do you mean ?
 

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