Search results
Results from the WOW.Com Content Network
Eustress is not defined by the stress or type, but rather how one perceives that stressor (e.g., a negative threat versus a positive challenge). Eustress refers to a positive response one has to a stressor, which can depend on one's current feelings of control, desirability, location, and timing of the stressor.
For points inside a spherically symmetric distribution of matter, Newton's shell theorem can be used to find the gravitational force. The theorem tells us how different parts of the mass distribution affect the gravitational force measured at a point located a distance r 0 from the center of the mass distribution: [13]
Conversely, as two massive objects move towards each other, the motion accelerates under gravity causing an increase in the (positive) kinetic energy of the system and, in order to conserve the total sum of energy, the increase of the same amount in the gravitational potential energy of the object is treated as negative.
For two pairwise interacting point particles, the gravitational potential energy is the work that an outside agent must do in order to quasi-statically bring the masses together (which is therefore, exactly opposite the work done by the gravitational field on the masses): = = where is the displacement vector of the mass, is gravitational force acting on it and denotes scalar product.
The latter may be body forces (such as gravity or magnetic attraction), that act throughout the volume of a material; [16]: 42–81 or concentrated loads (such as friction between an axle and a bearing, or the weight of a train wheel on a rail), that are imagined to act over a two-dimensional area, or along a line, or at single point.
In combination, the equatorial bulge and the effects of the surface centrifugal force due to rotation mean that sea-level gravity increases from about 9.780 m/s 2 at the Equator to about 9.832 m/s 2 at the poles, so an object will weigh approximately 0.5% more at the poles than at the Equator.
If an object falls from one point to another point inside a gravitational field, the force of gravity will do positive work on the object, and the gravitational potential energy will decrease by the same amount. Gravitational force keeps the planets in orbit around the Sun. Consider a book placed on top of a table.
During the first 0.05 s the ball drops one unit of distance (about 12 mm), by 0.10 s it has dropped at total of 4 units, by 0.15 s 9 units, and so on. Near the surface of the Earth, the acceleration due to gravity g = 9.807 m/s 2 ( metres per second squared , which might be thought of as "metres per second, per second"; or 32.18 ft/s 2 as "feet ...