This document defines and explains key concepts related to motion in one dimension, including: 1) Displacement is the distance an object moves along a straight track from a starting point, and is plotted against time on a graph. 2) Velocity is the rate of change of an object's displacement over time, and requires both magnitude and direction. 3) Acceleration is the rate of change of an object's velocity over time, and can be positive if velocity is increasing or negative if decreasing.

1. MOTION IN ONE DIMENSION

2. Definition
• Motion is defined as change in position of a
body over time with respect to the
surrounding.
• Motion in one dimension is consider a motion
of a body along a straight track. The subject of
motion in physics is called a, "body". The
displacement (x), velocity (v), and acceleration
(a). All of these three are linked together.

3. Displacement
• Displacement is defined as the distance (x) a
one-dimensional object is from a center point,
or an origin. Displacement is plotted against
time in a curved graph. A body, in motion in
one dimension, can only move left and right.

4. Acceleration
• Acceleration is the rate of change of velocity
with time. A body with a positive acceleration
is gaining velocity over time. A body with a
negative acceleration is losing velocity over
time.

5. Velocity
• Velocity is defined as the rate of which
displacement changes over time. The higher
the velocity, the faster a body is moving. It is a
vector quantity i.e. it requires both magnitude
and direction. Velocity can be zero also if the
total displacement is zero, and this is only
when the body after travelling a certain
distance in any direction comes to rest at the
same point where it started.

6. Motion with Constant Velocity
• This is the simplest type of motion in one
dimension. A body will have motion with
constant velocity if it is sliding over a
horizontal surface with minimal friction.
• Motion with constant velocity is plotted on a
graph of displacement vs. time.

7. Examples
• Example 1: A particle starting at the origin has
moved 27 m in 9 s.
• Example 2: A particle starting 23 m from the
origin has moved to 43 m in 5 s.