PHYSICS Flashcards
two major systems of units used in the world
SI units and English units
Also known as
the metric system
SI units
Also known as the customary or imperial
system
English units
The acronym
“SI” is derived from the
French Système International
how close a
measurement is to the correct
value for that measurement.
Accuracy
a measurement
system refers to how close the
agreement is between repeated
measurements (which are
repeated under the same
conditions)
precision
is a quantitative measure of how
much your measured values deviate
from a standard or expected value.
Uncertainty
SI units are part of the metric
system. The metric system is
convenient for scientific and
engineering calculations
because the units are
categorized by factors of 10.
Metric Prefixes
The factors contributing to uncertainty in a
measurement include:
● Limitations of the measuring device
● The skill of the person making the
measurement
● Irregularities in the object being measured
● Any other factors that affect the outcome
(highly dependent on the situation).
the branch of physics which deals with the cause and effects
of motion of a particle, rigid objects and deformable bodies etc.
Mechanics
Mechanics is classified under two streams namely
Kinematics and Dynamics
The word Kinematics means
“science of motion”.
Kinematics
The branch of mechanics
which is concerned about the
causes (i.e. the force, torque)
that cause of motion of
bodies.
Dynamics
Concept of a point object/point
mass/particle
When the size of the object is much less in
comparison to the distance covered by the
object then the object is considered as a
point object.
A certain amount of matter limited in all directions
and consequently having a finite size, shape and occupying
some definite space is called a body.
BODY -
A body is said to be rigid if the distance between any pair of its constituent particles remains unchanged.
RIGID BODY
The smallest part of matter with zero dimension
which can be described by its mass and position is defined as
a particle. Thus, a particle has only a definite position, but no
dimension. In the problems we are going to discuss, we will
consider a body to be a particle for the sake of simplicity.
Particle
A body is said to be in
motion if its position changes
continuously w.r.t. the
surroundings (or with
respect to an observer) with
the passage of time.
Motion
An object is said to be at rest
if it does not change its
position w.r.t. its
surroundings with the
passage of time.
Rest
It is a system to which a set of coordinates are attached and with reference to which observer describes
any event.
Frame of Reference
The motion of a moving car, a person
running, a stone being dropped.
LINEAR MOTION
The motion of an electric fan, motion of
earth about its own axis.
ROTATIONAL MOTION
The motion of a simple pendulum, a body
suspended from a spring (also called to
and fro motion).
OSCILLATORY MOTION
The position of a particle refers to its location
in the space at a certain moment of time. It
is concerned with the question – “where is
the particle
Position Vector
The change in the position of a moving object
is known as displacement. It is the vector
joining the initial position of the particle to
its final position during an interval of time
Displacement Vector
The length of the actual path travelled by a particle during a given time interval is called as distance. The distance travelled
is a scalar quantity which is quite different from displacement. In general, the distance travelled between two
points may not be equal to the magnitude of the displacement between the same points.
Distance
may be either positive or zero
but it can not be negative
Distance
the length of the path
traveled by a body in any direction.
Distance
The between two given points
depends upon the path chosen.
Distance
it is always positive.
Distance
scalar quantity
Distance
will never decrease
Distance
the shortest
distance between the initial and the
final positions of a body in the
direction of the point of the final
position.
Displacement
two points is
measured by the straight path
between the points.
Displacement
may be positive as
well as negative and even zero.
Displacement
a vector quantity
Displacement
may decrease
Displacement
has magnitude and direction
VECTOR FORCE
a resultant force acting on object
NET FORCE
An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force
NEWTON’S FIRST LAW OF MOTION
