Page 34 - mechanics

Chapter – 6 Kinematics of a Particle

displacement of the particle denoted by x is given by

x = xf - xi (6.1)

From this definition we see that x is positive if xf is greater

than xi and negative if xf is less than xi.

It is very important to recognize the difference between

displacement and distance traveled.

Distance is the length of a path followed by a particle.
.‫النساف هم طول النساا الذي قطعه الجسيم‬

Displacement is an example of a vector quantity whereas
distance is a scalar positive quantity.

Note that in Figure 11.1.b, the smooth curve drawn through
the six points given in table 11.1 is only a possibility of the
actual motion of the car. If the smooth curve does represent the
actual motion of the car, the graph contains information about
the entire 50-s interval during which we watch the car move. It
is much easier to see changes in position from the graph than
from a verbal description or even a table of numbers. A
common way of comparing these different motions is to divide
the displacement x that occurs between two clock readings by
the length of that particular time interval t. This ratio has been
given a special name-average velocity.

5