Skip to main content
added 35 characters in body
Source Link
Bob D
  • 77.9k
  • 6
  • 58
  • 152

I can appreciate your apparent frustration with the inconsistencies.

The Resnick statement "Work is energy transferred to or from an object by means of a force acting on the object" doesn’t include displacement. So as a definition of work it seems incomplete, unless you’ve left stuff out.

The Wikipedia article, which is similar to Feynman, is better, but it still lacks an important qualification, which is the displacement has to occur at the point where the force is applied. Static friction the ground applied to the drive wheel of a car causes it to accelerate without skidding, but the ground does no work (it doesn't transfer energy to the car). That's because there is no displacement of the point of application of the static friction force on the tire.

Taylor is incomplete (at least based on what you quoted is). It sounds like the work energy theorem which is the net work done on an object equals its change in kinetic energy. I do work pushing a box at constant speed along a floor with kinetic friction even though there is no change in kinetic energy while I'm pushing it. That's because my work is not the net work done on the box. The net work is zero because my positive work equals the negative work done by kinetic friction for a net work of zero.

My view is the definition must include displacement of the point of application of the force.

Hope this helps.

I can appreciate your apparent frustration with the inconsistencies.

The Resnick statement "Work is energy transferred to or from an object by means of a force acting on the object" doesn’t include displacement. So as a definition of work it seems incomplete.

The Wikipedia article, which is similar to Feynman, is better, but it still lacks an important qualification, which is the displacement has to occur at the point where the force is applied. Static friction the ground applied to the drive wheel of a car causes it to accelerate without skidding, but the ground does no work (it doesn't transfer energy to the car). That's because there is no displacement of the point of application of the static friction force on the tire.

Taylor is incomplete (at least what you quoted is). It sounds like the work energy theorem which is the net work done on an object equals its change in kinetic energy. I do work pushing a box at constant speed along a floor with kinetic friction even though there is no change in kinetic energy while I'm pushing it. That's because my work is not the net work done on the box. The net work is zero because my positive work equals the negative work done by kinetic friction for a net work of zero.

My view is the definition must include displacement of the point of application of the force.

Hope this helps.

I can appreciate your apparent frustration with the inconsistencies.

The Resnick statement "Work is energy transferred to or from an object by means of a force acting on the object" doesn’t include displacement. So as a definition of work it seems incomplete, unless you’ve left stuff out.

The Wikipedia article, which is similar to Feynman, is better, but it still lacks an important qualification, which is the displacement has to occur at the point where the force is applied. Static friction the ground applied to the drive wheel of a car causes it to accelerate without skidding, but the ground does no work (it doesn't transfer energy to the car). That's because there is no displacement of the point of application of the static friction force on the tire.

Taylor is incomplete (at least based on what you quoted). It sounds like the work energy theorem which is the net work done on an object equals its change in kinetic energy. I do work pushing a box at constant speed along a floor with kinetic friction even though there is no change in kinetic energy while I'm pushing it. That's because my work is not the net work done on the box. The net work is zero because my positive work equals the negative work done by kinetic friction for a net work of zero.

My view is the definition must include displacement of the point of application of the force.

Hope this helps.

Correction
Source Link
Bob D
  • 77.9k
  • 6
  • 58
  • 152

I can appreciate your apparent frustration with the inconsistencies.

I dislike theThe Resnick statement "Work is energy transferred to or from an object by means of a force acting on the object", because that would apply if I say, applied a force to a wall that doesn't move doesn’t include displacement. Of course I do no physicsSo as a definition of work (though I expend energy)it seems incomplete.

The Wikipedia article, which is similar to Feynman, is better, but it still lacks an important qualification, which is the displacement has to occur at the point where the force is applied. Static friction the ground applied to the drive wheel of a car causes it to accelerate without skidding, but the ground does no work (it doesn't transfer energy to the car). That's because there is no displacement of the point of application of the static friction force on the tire.

Taylor is incomplete (at least what you quoted is). It sounds like the work energy theorem which is the net work done on an object equals its change in kinetic energy. I do work pushing a box at constant speed along a floor with kinetic friction even though there is no change in kinetic energy while I'm pushing it. That's because my work is not the net work done on the box. The net work is zero because my positive work equals the negative work done by kinetic friction for a net work of zero.

My view is the definition must include displacement of the point of application of the force.

Hope this helps.

I can appreciate your apparent frustration with the inconsistencies.

I dislike the Resnick statement "Work is energy transferred to or from an object by means of a force acting on the object", because that would apply if I say, applied a force to a wall that doesn't move. Of course I do no physics work (though I expend energy).

The Wikipedia article, which is similar to Feynman, is better, but it still lacks an important qualification, which is the displacement has to occur at the point where the force is applied. Static friction the ground applied to the drive wheel of a car causes it to accelerate without skidding, but the ground does no work (it doesn't transfer energy to the car). That's because there is no displacement of the point of application of the static friction force on the tire.

Taylor is incomplete (at least what you quoted is). It sounds like the work energy theorem which is the net work done on an object equals its change in kinetic energy. I do work pushing a box at constant speed along a floor with kinetic friction even though there is no change in kinetic energy while I'm pushing it. That's because my work is not the net work done on the box. The net work is zero because my positive work equals the negative work done by kinetic friction for a net work of zero.

My view is the definition must include displacement of the point of application of the force.

Hope this helps.

I can appreciate your apparent frustration with the inconsistencies.

The Resnick statement "Work is energy transferred to or from an object by means of a force acting on the object" doesn’t include displacement. So as a definition of work it seems incomplete.

The Wikipedia article, which is similar to Feynman, is better, but it still lacks an important qualification, which is the displacement has to occur at the point where the force is applied. Static friction the ground applied to the drive wheel of a car causes it to accelerate without skidding, but the ground does no work (it doesn't transfer energy to the car). That's because there is no displacement of the point of application of the static friction force on the tire.

Taylor is incomplete (at least what you quoted is). It sounds like the work energy theorem which is the net work done on an object equals its change in kinetic energy. I do work pushing a box at constant speed along a floor with kinetic friction even though there is no change in kinetic energy while I'm pushing it. That's because my work is not the net work done on the box. The net work is zero because my positive work equals the negative work done by kinetic friction for a net work of zero.

My view is the definition must include displacement of the point of application of the force.

Hope this helps.

Source Link
Bob D
  • 77.9k
  • 6
  • 58
  • 152

I can appreciate your apparent frustration with the inconsistencies.

I dislike the Resnick statement "Work is energy transferred to or from an object by means of a force acting on the object", because that would apply if I say, applied a force to a wall that doesn't move. Of course I do no physics work (though I expend energy).

The Wikipedia article, which is similar to Feynman, is better, but it still lacks an important qualification, which is the displacement has to occur at the point where the force is applied. Static friction the ground applied to the drive wheel of a car causes it to accelerate without skidding, but the ground does no work (it doesn't transfer energy to the car). That's because there is no displacement of the point of application of the static friction force on the tire.

Taylor is incomplete (at least what you quoted is). It sounds like the work energy theorem which is the net work done on an object equals its change in kinetic energy. I do work pushing a box at constant speed along a floor with kinetic friction even though there is no change in kinetic energy while I'm pushing it. That's because my work is not the net work done on the box. The net work is zero because my positive work equals the negative work done by kinetic friction for a net work of zero.

My view is the definition must include displacement of the point of application of the force.

Hope this helps.