What does it mean if you have negative mass or negative weight?

Answer 1

negative mass
A hypothetical counterpart to ordinary (positive) mass. Although it is not known if negative mass exists, or even if its existence is theoretically possible, a number of scientists have speculated on its properties. Among these are Hermann Bondi1 in the 1950s, Banesh Hoffman (1906-1986), of the City University, New York, in the 1960s and '70s, and Robert Forward,2 in the context of spacecraft propulsion, in the 1980s. In both Newton's and Einstein's theories of gravity, negative mass is a requirement for antigravity to exist.

Answer 2

deann's answer is right on point...F = -ma makes no sense...nor does E = -mc^2. What's negative energy? Since energy is the ability to do work or cause a change, would negative energy be the ability to not do work and to not cause a change?

On the other hand, negative weight has some meaning. For example, perhaps you've heard of negative g's, which can be felt when an aircraft noses over suddenly. Things not tied down float up; they are exhibiting a negative weight of sorts. Their mass is still positive, but their net weight has become negative.

If the weight of a body at rest is W = mg, where g is the normal acceleration due to gravity; then when pulling negative g's, that weight becomes -W = m(-g) In fact, the so-called negative g's come from centripetal force, which is that force that tends to throw things out from the center of a turn.

Answer 3

If there were some form of matter with a negative mass, how would it behave? The first insight is that it would move in a direction opposite to that in which it is pushed. So, if we have a lump of mass of, say -3 grams, and we push it (i.e. apply a force) to the right, it will move (i.e. accelerate) to the left. The harder we try to push it to the right, the more fervently it would move to the left. This follows from Newton's Law, F = ma, which clearly shows that if a positive force, F, is applied to a negative mass, -m, the acceleration, a, must be negative (i.e. opposite to the direction of the force) for the equation to hold.

Answer 4

No negative mass. negative weight may be You can call the hot air balloon to have negative weight. but they do have still only mass no negative mass

Answer 5

You are experiencing zero G, no gravity caused by angular momentum or from free fall where gravity has no effect because there is nothing pressing against you to cause a sensation of weight.

Space travel is a free fall situation. Falling off a cliff too would give you that effect, well for a few seconds. Except very suddenly gravity will make itself painfully known.

Answer 6

Negative mass - Your overall composition of antimatter

Negative Weight - Relative to planet. It means you have done something to make you near "weightlessness" ie. Attaching 5 million helium balloons to you.

Answer 7

It means you have the wrong sign in one of your other variables. Something else needs to be considered negative, probably gravity since it is directed downward.

Answer 8

how can a mass be negative ?
you cannot have a negative weight..
your postulate is completely wrong

Answer 9

I found the introduction to this article helped a lot.

Answer 10

You have just entered the twilight zone