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drag The slowing force exerted by air or other fluid surrounding a moving object.
force An influence that tends to change the motion of a body or produce motion or stress in a stationary body.
erratic An adjective that describes something that happens at unpredictable intervals or a behavior that is unpredictable.
friction Resistance to motion that arises when one object moves over another.
physics The scientific study of the nature and properties of matter and energy. Classical physics is an explanation of the nature and properties of matter and energy that relies on descriptions such as Newton’s laws of motion. Quantum physics, a field of study which emerged later, is a more accurate way of explaining the motions and behavior of matter. A scientist who works in that field is known as a physicist.
resistance (as in drug resistance) The reduction in the effectiveness of a drug to cure a disease, usually a microbial infection.
statistics he practice or science of collecting and analyzing numerical data in large quantities.
symmetry In geometry, the property of being indistinguishable from a shifted, rotated or reflected image of the same object. For example, the letter X looks the same whether reflected in a mirror or turned upside down — two different kinds of symmetry. The opposite of symmetry is asymmetry.
trajectory The path traced by a flying object.
turbulence The chaotic, swirling flow of air. Airplanes that run into turbulence high above ground can give passengers a bumpy ride.
wind tunnel A facility used to study the effects of air moving past solid objects, which often are scale models of real-size items such as airplanes and rockets. The objects typically are covered with sensors that measure aerodynamic forces like lift and drag. Also, sometimes engineers inject tiny streams of smoke into the wind tunnel so that airflow past the object is made visible.