Stuff that can't be right in relativity

[Pete]

Why is the mass moving but the planet not moving? They are at rest with respect to each other.

Why are they at rest with respect to each other? I was addressing the specific problem of an observer at rest in a gravitational field (i.e. at rest with respect to the source of gravity, e.g. at rest in a uniform gravitational field) in which the scale is at rest but for which the body is moving with respect to this frame, i.e. the planent's frame of reference.

Mass being a vector is one of the issues folks have with this definition of mass.

I don't see that mass, as defined in this sense, is a vector quantity. A vector being functionally dependant on another vector (acceleration) doesn't make a lot of sense. I wouldn't define mass in that way myself. However it is very useful in certain kinds of problems, of which this is one.

 

Pete

[swansont]

Why are they at rest with respect to each other? I was addressing the specific problem of an observer at rest in a gravitational field (i.e. at rest with respect to the source of gravity, e.g. at rest in a uniform gravitational field) in which the scale is at rest but for which the body is moving with respect to this frame, i.e. the planent's frame of reference.

 

It's the scenario I described. An object on a scale on a planet, and a second observer moving with respect to the planet.

 

 

I don't see that mass, as defined in this sense, is a vector quantity. A vector being functionally dependant on another vector (acceleration) doesn't make a lot of sense. I wouldn't define mass in that way myself. However it is very useful in certain kinds of problems, of which this is one.

 

Pete

 

Why do you denote transverse mass? Presumably it's different than longitudinal mass. It's no longer a scalar, per se, if you have to assign those tags to it.

[Pete]

It's the scenario I described. An object on a scale on a planet, and a second observer moving with respect to the planet.

I see. I was doing something different though. I will solve the exact problem that you described and post the results later today.

Why do you denote transverse mass? Presumably it's different than longitudinal mass. It's no longer a scalar, per se, if you have to assign those tags to it.

Inertial mass (akak relativistic mass) is not a scalar either. The transverse mass as the exact same value as the relativistic mass. However the longitudinal mass is different and has the value [math]m_t = \gamma^3 m_0[/math]. That's why one has to assign different names to them. The term transverse mass comes from the fact that when the motion is transverse to the force then the force is given by F = m_ta.

 

The math is shown in one of my web pages at

http://www.geocities.com/physics_world/sr/long_trans_mass.htm

 

Pete