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1. Basic Physics

2. Basic Physics

9. In physics, motion is a change in position of an object with respect to time. Motion is
typically described in terms of displacement, distance (scalar), velocity, acceleration,
time and speed. Motion of a body is observed by attaching a frame of reference to
an observer and measuring the change in position of the body relative to that frame.
Motion

10. Types of Motion
Linear Motion (রৈখিক গখি)
Rotational Motion (ঘূর্ ণমান গখি)
Rectilinear (সৈলরৈিাগামী)
Periodic motion (সময়কাল গখি)
Vibratory motion (কম্পনশীল)

11. Types of Motion
Linear Motion (রৈখিক গখি)
If a body is in motion along a straight line, that is, if the motion of a
body is restricted on a straight line its motion is called linear motion.
The motion of a car
in a straight street is linear motion.
Rotational Motion (ঘূর্ ণমান গখি)
If a body is in motion along a straight line, that is, if the motion of a
body is restricted on a straight line its motion is called linear motion.
The motion of a car
in a straight street is linear motion.

12. Types of Motion
Rectilinear (সৈলরৈিাগামী)
When a body moves along a straight line in such a way that each
particle of the body travels the same distance at the same time in the same direction.
If a book is pushed to shift from one end to the other of a table without rotation, the
motion will be rectilinear because all the particles of the book travel the equal
distance, at equal time in the same direction
Translational motion (অনুবাদমূলক গখি)
Translational motion is the motion of body where body moves in the linear path. It is
the motion in which all points of a moving body move uniformly in the same line or
direction.

13. Types of Motion
Periodic motion (সময়কাল গখি)
If the motion of a moving particle is such that it passes through adefinite point along
the path of its motion in the same direction in a definite interval of
time, this type of motion is called periodic motion. This motion can be circular,
elliptical
or rectilinear. The motion of the hands of a clock, the motion of earth round the sun, the
motion of piston in the cylinder of a steam or petrol engine etc.
The time interval at which a particle of periodic motion passes through a definite point
from the same direction repeatedly is called its time p

14. Types of Motion
Vibratory motion (কম্পনশীল)
If a body executing periodic motion moves in a definite direction
for one half of its time period and exactly for the other half in the opposite
direction then this motion is called vibratory motion. Motion of a simple
pendulum, motion of vibrating tuning fork and the motion of string of
guitar.

15. Scalar & Vector quantity
Scalar quantity : Physical quantities which can be fully expressed by magnitude only
are called scalar quantities. Length, mass, speed, work, energy, time, temperature etc
are the examples of scalar quantities.
Vector quantity : Physical quantity which need both magnitude and direction to be
fully expressed are called vector quantities. Displacement, velocity, acceleration, force,
electric intensity etc are the examples of vector quantities.
Table 2.1 Shows that vectors are expressed by magnitude and direction whereas scalars
are expressed by magnitude only

24. Motion of falling bodies
Gravity : Every particle of this universe attracts towards each other. The force of
attraction between any two bodies or particles in this universe is called ``Gravitation’’. If
earth is one of the two bodies, then the force of attractions is called gravity, that is, the
attraction of the earth on any other body is called gravity. There is a law of Newton
about this attraction between any two bodies of the universe is known as Newton’s law
of gravitation.
We know from the Newton’s second law of motion that when a force acts on a body, it
acts acceleration. So, acceleration of a body is produced due to the force of gravity as
well. This acceleration is called acceleration due to gravity
The rate of increase of velocity of a freely falling body on earth due to force of gravity is
called the acceleration due to gravity. The acceleration due to gravity is represented by
the letter g.

25. Laws of falling bodies are :
First Law : All bodies falling from rest and from the same height without any resistance traverse
equal distance in equal time
Second Law : The velocity (v), acquired by a freely falling body from rest in a given
time (t) is directly proportional to time that is, v ∝ t
Third Law : The distance (h) traversed by a freely falling body from rest in a given time
(t) is directly proportional to the square of the time, that is, h ∝ t2.

30. Momentum

40. Energy

41. Energy

42. Energy