50
Mechanical energy stored in the human body powers the movement of matter by
muscles.
Radiant energy is energy emitted as waves. Human body uses energy of sunlight
to convert a compound in skin cells to vitamin D. The human eye evolved to see
“visible light.” Electrical energy, supplied by electrolytes in body fluids and cells,
help transmit information in nerve cells.
Changes in the physical environment, such as radiation, temperature, and force
(due to wind, falling objects during earthquake, rainfall, etc.), do have their implications on human health.
We do not have complete control on physical activities, such as heartbeat, passage of electrical impulse in nerve cells, flow of body fluids in our body, which are
directly linked to our environment. Further physical damage to body can occur due
to natural and anthropogenic disasters such as earthquake, flood, road/industrial
accidents, wars, and mutiny. With better understanding of physics, the concerned
experts can advise decision makers to take precautionary measures or corrective
action to safeguard the public health to the extent possible.
2.2 General Physics
Physics is a specialization of science that is concerned with properties of energy as
well as matter. It covers an array of sub-specialization and topics that include
mechanics, magnetism, light and other radiation, heat transfer, electricity, sound,
and the structure of atoms.
Understanding the structure of atoms forms the foundation to chemistry; it is
often discussed in chemistry as well. Since the structure of atoms has been discussed in the previous chapter, it will not be discussed again. Some of the frequently
used terms in physics are listed in Table 2.1.
Nature has four fundamental forces that exist in the environment:
1. Electromagnetic force
2. Gravitational force
3. Strong nuclear force
4. Weak nuclear force
The electromagnetic force is the sum of all electrical and magnetic forces. The
strong nuclear force holds protons and neutrons in the nuclei of atoms together. The
weak nuclear force is the interactions between subatomic particles responsible for
radioactive decay. Gravitational force acts between two objects.
As per Newton’s universal law of gravitation, gravitational force is directly proportional to the product (multiplication) of their masses and inversely proportional
to the square of the distance between geographical centers.
In Fig. 2.1, bodies with mass m 1 and m 2 attract each other. Since forces exerted
by each other are in opposite directions,
2 Fundamentals of Physics for Environmental and Medical Professionals
Mechanical energy stored in the human body powers the movement of matter by
muscles.
Radiant energy is energy emitted as waves. Human body uses energy of sunlight
to convert a compound in skin cells to vitamin D. The human eye evolved to see
“visible light.” Electrical energy, supplied by electrolytes in body fluids and cells,
help transmit information in nerve cells.
Changes in the physical environment, such as radiation, temperature, and force
(due to wind, falling objects during earthquake, rainfall, etc.), do have their implications on human health.
We do not have complete control on physical activities, such as heartbeat, passage of electrical impulse in nerve cells, flow of body fluids in our body, which are
directly linked to our environment. Further physical damage to body can occur due
to natural and anthropogenic disasters such as earthquake, flood, road/industrial
accidents, wars, and mutiny. With better understanding of physics, the concerned
experts can advise decision makers to take precautionary measures or corrective
action to safeguard the public health to the extent possible.
2.2 General Physics
Physics is a specialization of science that is concerned with properties of energy as
well as matter. It covers an array of sub-specialization and topics that include
mechanics, magnetism, light and other radiation, heat transfer, electricity, sound,
and the structure of atoms.
Understanding the structure of atoms forms the foundation to chemistry; it is
often discussed in chemistry as well. Since the structure of atoms has been discussed in the previous chapter, it will not be discussed again. Some of the frequently
used terms in physics are listed in Table 2.1.
Nature has four fundamental forces that exist in the environment:
1. Electromagnetic force
2. Gravitational force
3. Strong nuclear force
4. Weak nuclear force
The electromagnetic force is the sum of all electrical and magnetic forces. The
strong nuclear force holds protons and neutrons in the nuclei of atoms together. The
weak nuclear force is the interactions between subatomic particles responsible for
radioactive decay. Gravitational force acts between two objects.
As per Newton’s universal law of gravitation, gravitational force is directly proportional to the product (multiplication) of their masses and inversely proportional
to the square of the distance between geographical centers.
In Fig. 2.1, bodies with mass m 1 and m 2 attract each other. Since forces exerted
by each other are in opposite directions,
2 Fundamentals of Physics for Environmental and Medical Professionals