Physics 1
Physics 1
Physics 1
CHAPTER 1
Science deals with concept in seeking to extend the range of our experience and to reduce it to
order.
Physics deals with concepts which describe properties of matter, energy, space and time.
Measurement in simple cases means comparing things with a standard to see how many times
as big it is.
Mechanics - the branch of applied mathematics dealing with motion and forces producing motion.
THREE FUNDAMENTAL QUANTITIES IN MECHANICS
Length - is the measured dimension of an object. (i.e centimetre, meter, foot, etc. )
Mass in physics, the quantity of matter in a body regardless of its volume or of any forces acting
on it. (i.e grams, kilograms, slugs, etc. )
Time - is what a clock reads, also it is the thing that is measured as seconds, minutes, hours, years,
etc.
For each fundamental quantity there is an arbitrarily chosen fundamental unit. Other units based
on combination of the fundamental units are called derived units. A complete set of unit, both
fundamental and derived is called systems of units.
SYSTEMS OF UNITS
1. MKSA systems a system on the fundamental units of the meter as a unit of length, kilogram
as a unit of mass, and second as a unit of time.
2. CGS systems formerly widely used in science , is based upon the centimetre as a unit of
length, the gram as a unit of mass, and the second as a unit of time.
3. FPS system is also called as the British gravitational system. This system of unit is based
upon the foot as a unit of length, the pound as a unit of mass, and second as a unit of time.
Example1:
Change 115 in. to centimeters?
Example 2:
Express 60 mi. / h in feet per second?
Example 3:
The following readings were obtained when measuring the dimensions of a long, thin rectangular
object 0.25 km long, 25 cm wide, and 25 mm thick. What is its volume in cubic meters?
Example 4:
Five coins are placed on a balance and are found to have the following masses: 5.25 g, 4.95 g, 5.05
g, 4.90 g, and 5.10 g. If the standard weight for these coins is 5.00 g, find the average percentage
deviation of these readings?
Example 5:
Density in cgs units is expressed in grams per cubic centimetre and in mks units in kilograms per
cubic meter. Convert a density of 7.45 g / cm3 to mks units?
Many important problems confronting the physicist and engineers involve in several forces acting
on a body under circumstances in which they produce no change in the motion of the body. The
state in which there is no change in the motion of a body is called equilibrium. A body in
equilibrium may be at rest but not necessarily to be at rest, it may be moving with uniform speed
in a straight line or rotating uniformly around a fixed axis.