Negative force

Adhesiveness, defined as the work necessary to overcome the attractive forces between the surface of the sample and the surface of other materials with which the food comes into contact, e.g. tongue, teeth, palate, etc. (Szczesniak, 1963), is given on the texturometer curve by the negative force area, representing the work needed to pull out the plunger from the sample. This parameter s value may be considered an evaluation of stickiness of jelly. Fracturability, also called brittleness, is given by the measure (%) of the plunger path into the jelly when it breaks. 

This assumes that the xy plane is horizontal. If the y direction is vertical, the total weight of the bend, including the fluid inside, could be included as an additional (negative) force component due to gravity. The magnitude and... 

It is important to appreciate that the sign conventions do not dictate the direction in which a stress physically acts, they simply specify the directions chosen for measuring the stresses. If a stress physically acts in the opposite direction to that specified in the convention being used, then the stress will be found to have a negative value, just as in elementary mechanics where a negative force reflects the fact that it acts in the opposite direction to that taken as positive. 

The saddle point on a three-dimensional potential-energy surface, characterized by one negative force constant in the harmonic force constant matrix. 

Plants live in a world comprised of numerous limiting and potentially destructive forces. A developing biosystem is subjected to the integrated influence of all positive and negative forces that interact simultaneously upon the system. In the complex natural environment, a practical evaluation of the impact of any one factor should not be made without due respect given to the relative influences of other controlling and limiting factors which can vary plant responses and perturb the system. 

An emotion can be an especially negative force if you allow it to attach you to a particular viewpoint, perception or stance. Changing a perception or belief, even in the face of irrefutable contradictory evidence, may then be resisted. 

A stationary point could of course be characterized just from the number of negative force constants, but the mass-weighting requires much less time than calculating the force constants, and the frequencies themselves are often wanted anyway, for example for comparison with experiment. In practice one usually checks the nature of a stationary point by calculating the frequencies and seeing how many imaginary frequencies are present a minimum has none, a transition state one, and a hilltop more than one. If one is seeking a particular transition state the criteria to be satisfied are ... 

Now suppose a negative force field is included (i.e., include the force due to gravity which imparts an additional downward velocity vt on the particles this is the terminal settling velocity). Then... 

---