Surprising insights about debris flows on Mars

The period that liquid water was present on the surface of Mars may have been shorter than previously thought. Channel landforms called gullies, previously thought to be formed exclusively by liquid water, can also be formed ...

India's 'drone sisters' steer farming and social change

Once a housewife in rural India, Sharmila Yadav always wanted to be a pilot and is now living her dream remotely, flying a heavy-duty drone across the skies to cultivate the country's picturesque farmlands.

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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