Motion (physics) In physics, motion is a change in position of an object over time. Motion is described in terms of displacement, distance, velocity, acceleration, time and speed. Motion of a body is observed by attaching a frame of reference to an observer and measuring the change in position of the body relative to that frame.
ADHD, medication rates in U.S. continue to rise. Attention deficit hyperactivity disorder (ADHD) rates in the United States continue to rise, with 11 percent of children ages 4-17 having received a diagnosis in 2011, according to a study released Friday.
Attention deficit hyperactivity disorder (ADHD) is one of the most common childhood disorders. ADHD is a broad term, and the condition can vary from person to person. There are an estimated 6.4 million diagnosed children in the United States, according to the Centers for Disease Control and Prevention. The condition is also known as attention deficit disorder (ADD), though this is considered an outdated term.