Immunology

Antibodies gather and form a circle for defensive attack

Antibodies play a crucial role in our immune system by linking antigen recognition with complement activation for attacking foreign cells. Using high-speed atomic force microscopy, collaborative groups, including researchers ...

Health

USPSTF recommends behavioral counseling for STI prevention

The U.S. Preventive Services Task Force (USPSTF) recommends behavioral counseling for sexually active adolescents and for adults with increased sexually transmitted infection (STI) risk. These recommendations form the basis ...

HIV & AIDS

Determinants of employability of people living with HIV/AIDS

People living with HIV/AIDS may face discrimination in employers' hiring practices. A study published in the American Journal of Industrial Medicine found that medical and socioeconomic factors may hinder their employment.

page 1 from 23

Force

In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate, or which can cause a flexible object to deform. Force can also be described by intuitive concepts such as a push or pull. A force has both magnitude and direction, making it a vector quantity. Newton's second law, F=ma, was originally formulated in slightly different, but equivalent terms: the original version states that the net force acting upon an object is equal to the rate at which its momentum changes.

Related concepts to force include: thrust, which increases the velocity of an object; drag, which decreases the velocity of an object; and torque which produces changes in rotational speed of an object. Forces which do not act uniformly on all parts of a body will also cause mechanical stresses, a technical term for influences which cause deformation of matter. While mechanical stress can remain embedded in a solid object, gradually deforming it, mechanical stress in a fluid determines changes in its pressure and volume.

This text uses material from Wikipedia, licensed under CC BY-SA