Is it possible that the force on a body is zero when its mass is zero?

[randomgamernerd]

Homework Statement

:[/B]
Ok, so my exams are coming and all sorts of crazy thoughts are banging my mind and now I have a question regarding a very simple law of physics, the funniest part, this is my last month of high school life...so at this juncture of life, i am having this crazy question.

MY QUESTION IS if F_net=ma,
then is it possible that we have a body which is accelerating but its mass is zero(i don't mean negligible, but zero) and so we are unable to detect the force?
This seems quite crazy because when i say the body has absolutely zero mass, it means it does not exist, so this question should not arise.
Now let me explain what I mean when I say the body has zero mass.
I mean that the body exists, and it has a mass, but because of some reason, it is unable to exhibit the properties of mass, so we are considering the mass to be zero.
I know a body traveling at speed of light has almost zero mass..

But I would like to know some other situation where mass of a body is zero, i mean, the mass exists, but is unable to exhibit mass like properties..

Homework Equations

: F=:ma[/B]

The Attempt at a Solution

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[PeroK]

Newton's laws apply to particles with mass.

Particles with zero mass appear in Special Relativity - they are called photons and represent light waves. But $F = ma$ is not applicable to them.

 

[randomgamernerd]

Newton's laws apply to particles with mass.

Particles with zero mass appear in Special Relativity - they are called photons and represent light waves. But $F = ma$ is not applicable to them.

yah. i understand that...but any other situation?

 

[Chestermiller]

A body having zero mass is just a limiting situation. Think syrofoam. In the limit, the forces on the body essentially always sum to zero, irrespective of the body’s acceleration. An example of this is when we encounter a “massless piston” within a cylinder, with the enclosed gas expanding irreversibly (very rapidly)

 

[CWatters]

But I would like to know some other situation where mass of a body is zero, i mean, the mass exists, but is unable to exhibit mass like properties..

You could mount an object that has mass (M) on a robotic arm programmed to respond in such a way as to make it appear as if the mass was less (m).

For example if you applied a force F to the object the arm would add an additional force so that the mass accelerated at a=F/m rather than a=F/M.

Think human exoskeleton giving you super lifting powers :-)

However if you wanted it to reduce the apparent mass m to zero the robot would need to be able to accelerate infinitely fast which isn't possible.

 

[randomgamernerd]

You could mount an object that has mass (M) on a robotic arm programmed to respond in such a way as to make it appear as if the mass was less (m).

For example if you applied a force F to the object the arm would add an additional force so that the mass accelerated at a=F/m rather than a=F/M.

Think human exoskeleton giving you super lifting powers :-)

However if you wanted it to reduce the apparent mass m to zero the robot would need to be able to accelerate infinitely fast which isn't possible.

how will I program to make it appear as if mass was less than m? is this possible ? or just an example to make me understand?

 

[randomgamernerd]

A body having zero mass is just a limiting situation. Think syrofoam. In the limit, the forces on the body essentially always sum to zero, irrespective of the body’s acceleration. An example of this is when we encounter a “massless piston” within a cylinder, with the enclosed gas expanding irreversibly (very rapidly)

oh..right..

 

[CWatters]

how will I program to make it appear as if mass was less than m? is this possible ? or just an example to make me understand?

Was intended as a example but could be done. The arm would need to detect the applied force and accelerate the object as if a larger force had been applied. I guess this is similar to how power steering on a car works. When it fails you find out how hard it really is to turn the wheels.

 

[randomgamernerd]

o

Was intended as a example but could be done. The arm would need to detect the applied force and accelerate the object as if a larger force had been applied. I guess this is similar to how power steering on a car works. When it fails you find out how hard it really is to turn the wheels.

kay thanks