Sports medicine & Kinesiology

Football-loving states slow to enact youth concussion laws

States with college teams in strong conferences, in particular the Southeastern Conference (SEC), were among the last to take up regulations on youth concussions, according to a recent study. The study, which investigated ...

Cardiology

USPSTF finds evidence lacking for child HTN screening

(HealthDay)—The U.S. Preventive Services Task Force (USPSTF) concludes that current evidence is inadequate for assessing the balance of benefits and harms of screening children and adolescents for high blood pressure. These ...

Neuroscience

How does the brain process fear?

When a frightful creature startles you, your brain may activate its fear-processing circuitry, sending your heart racing to help you escape the threat. It's also the job of the brain's fear-processing circuits to help you ...

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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