Would artificially changing the mass of an object still follow kinetic conservation of energy?

[GrahamF]

Say you had a 1kg lead sphere that, by using a hypothetical form of antigravity, can be changed from a mass of 1g to 1t without affecting any other physical properties. if you pushed it so it was moving at say 1m/s then changed it's mass up or down; would the speed stay the same but the kinetic force changes, or would the kinetic force stay the same and the speed would change?

[Genady]

Some clarifications required:

1. If it is pushed, before the mass change, it is not moving with a constant speed, but rather accelerates.

2. What is "kinetic force"? I am familiar with "force" and with "kinetic energy", but not with "kinetic force".

3. What "antigravity" has to do with mass change?

[swansont]

42 minutes ago, GrahamF said:

Say you had a 1kg lead sphere that, by using a hypothetical form of antigravity, can be changed from a mass of 1g to 1t without affecting any other physical properties. if you pushed it so it was moving at say 1m/s then changed it's mass up or down; would the speed stay the same but the kinetic force changes, or would the kinetic force stay the same and the speed would change?

Once you decide that physical law doesn’t apply, you can’t use those laws to describe the behavior. It’s all interconnected.

[exchemist]

1 hour ago, GrahamF said:

Say you had a 1kg lead sphere that, by using a hypothetical form of antigravity, can be changed from a mass of 1g to 1t without affecting any other physical properties. if you pushed it so it was moving at say 1m/s then changed it's mass up or down; would the speed stay the same but the kinetic force changes, or would the kinetic force stay the same and the speed would change?

Once you break the rules of physics you are in a fantasy world in which all bets are off.

[Genady]

You can change the mass by attaching to the moving body "on the fly" two other bodies of equal mass coming to it from two sides with equal speed and moving with the same speed in the same direction as the central body. Can you rephrase you question for this scenario?

[studiot]

2 hours ago, GrahamF said:

Say you had a 1kg lead sphere that, by using a hypothetical form of antigravity, can be changed from a mass of 1g to 1t without affecting any other physical properties. if you pushed it so it was moving at say 1m/s then changed it's mass up or down; would the speed stay the same but the kinetic force changes, or would the kinetic force stay the same and the speed would change?

Firstly there is no law of conservation of kinetic energy, only conservation of total mechanical energy.

Secondly there is no need for magic or dragons as objects with mass obey the laws of mechanics without fuss or bother.

This includes the common situation of variable mass, for example a rocket steadily looses mass when the motor is firing.

 

Please study the proper laws of basic science more thoroughly before guessing.