Physics is the study of the forces, the energy,
and the matter that make up the Universe and
everything in it.. APPLIED PHYSICS uses the
discoveries of physics in medicine, engineering,
and other practical situations.
WHAT DO EQUATIONS TELL US?
An equation states that the amount to the left of
the equals sign is the same as the amount on the
right. Letters are used for physical properties – in the
equation F=ma, F is force, and ma means mass (m)
multiplied by acceleration (a). Some equations show
the results of an experiment, and others show the
predictions of a theory.WHAT DO PHYSICISTS STUDY?
Physicists investigate what atoms are made of, how
materials behave, and the forces that keep planets in
orbit. They also study heat, light, sound, electricity,
and magnetism. They try to discover the basic laws
that matter and energy obey. Discoveries are usually
written down as scientific. EQUATIONS.
WHAT ARE PHYSICAL PROPERTIES?
Physical properties are features that can be measured
as numbers – length, weight, and volume, for
example. Other physical properties include hardness,
density, elasticity (how flexible a material is),
conductivity (how well it conducts electricity or
heat), and reflectivity (how much light it reflects).
HOW DO PHYSICISTS WORK?
There are two main types of investigation in physics.
Experimental physicists work in laboratories,
designing experiments to measure physical properties
and processes. Theoretical physicists work with ideas,
equations, and models to uncover new laws of physics
that can explain or predict the results of experiments.Applied physicists use the basic laws of the physical
world to design useful tools and techniques for
many areas of science and technology, including
medicine, astronomy, meteorology, materials science,
and information technology.HOW IS PHYSICS USED IN MEDICINE?
Physics has been used to develop many valuable
medical instruments and techniques. Scanners, X-ray
machines, and laser surgery are based on discoveries
made by physicists, as are heart monitors and
radiation treatment for cancer.1 STOPPING DISTANCE
This equation shows how the stopping distance (d) of a braking car
depends on its speed, or velocity (v). The distance has two parts. 0.7v
(0.7 times the speed) is the distance travelled while the driver is reacting
(the thinking distance). 0.07v^2 is the distance travelled during braking.
The symbol^2 means the number multiplied by itself.Physics
4 MRI SCAN
With an MRI (magnetic resonance
imaging) scan, a doctor can look
inside the body without surgery.
MRI is based on the magnetic
properties of atomic nuclei,
discovered by physicists.ROLLERCOASTER 1
Designers used physics to make
sure this rollercoaster is safe, but
also fun. They use the basic laws
of motion to predict the forces
you will experience at every loop
and turn of the ride.APPLIED PHYSICS
d = 0. 7 v + 0. 07 v^2
EQUATIONS
An equation is a short way to write a
scientific idea. For example, the density
of a material is a measure of how tightly
packed the matter inside it is. The equation
density=mass/volume says that an object’s
density is its mass divided by its volume.FIND OUT MORE. Energy 166 • Forces 164 • Matter 156 • Measurements 155
SIR ISAAC NEWTON
English, 1642–1727
Isaac Newton made some
of the most important
scientific and mathematical
discoveries of all time. His
laws of motion and theories
of gravity explain how all
objects from atoms to planets
move. His theories of optics
(light) show that white light
is made of a spectrum of
colour light.physics