Question Boxers who receive hard punches to the head usually suffer from detached retinas, an injury in which the retina layer separates from the back of the eyeball. I'm just wondering how Newton's first and second laws can explain why a hard punch to the head can result in a detached retina.
Answer Sorry for the late reply, this got lost in my spam folder. Hard punches to the head result in impacts, which involve contact forces which are very large (decelerating the fighter's glove, fist, and arm from high speed to near zero over a very short amount of time requires a large acceleration, which corresponds to a very large force). A punch which makes contact to the eye will consequently be imparting forces to the eye itself. A punch which does not will still impact the head, causing it to accelerate (equal and opposite forces). That acceleration is shared by the eye, which means that there are contact forces between the skull and the back of the eye. Even though the eye is small, the retina is delicate. Repeated exposure to such shocks will exceed its ability to remain attached to the back of the eye. The detailed structure of such forces is quite complicated, and the threshold for damage is more of a question for a medical professional, but that's how newton's laws (F=ma, equal and opposite forces) plays in on a basic level.
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I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.
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