*Physical Health* Physical Health is health that does something to the human body (nutrition, physical body parts, etc..). Exercise, eating well and sleeping properly is positive. Eating junk food, no or little sleep and no or little exercise is negative and can lead to obesity, lower lifetime, diabetes, etc...
Social Doesn't seems like health, but it is. Social is health that does something with other people around (friends, family, etc..) Getting bullied, treated bad, etc is negative and leads to physical harm (getting bullied), and loneliness. The positive side is pretty much the opposite.
*Mental Health* Mental Health is something to do something internal, or with the brain. Mental can be something like IQ, thinking abilities, or what your thinking about (surroundings, learning, etc..). I can also mean your intelligence.