About the Author : Mickheal Navani is a Young physicists, and holds a BSc in Physics from Green land University India. He writes for majority of science blogs. Follow him @ twitter@MichealNavani
Preamble
Apart from kinematics, dynamics
deals with motion and the force that causes motion. Wikipedia defines dynamics as a branch of applied mathematics (specifically classical mechanics) concerned with the study of forces and torques and their effect on motion, as opposed to kinematics, which studies the motion of objects without reference to its causes. Thus,
dynamics is defined as the aspect of mechanics under which are we study about
the system of forces acting on a body that is in motion.
deals with motion and the force that causes motion. Wikipedia defines dynamics as a branch of applied mathematics (specifically classical mechanics) concerned with the study of forces and torques and their effect on motion, as opposed to kinematics, which studies the motion of objects without reference to its causes. Thus,
dynamics is defined as the aspect of mechanics under which are we study about
the system of forces acting on a body that is in motion.
Sir Isaac Newton had at a time carried out an elaborate work on motion
and the force that caused motion. Its
findings were summarized in what has now come to stay as the celebrated
Newton’s law of uniform motion. Thus,
having a clear understanding of force and motion requires an adequate
understanding of these laws.
and the force that caused motion. Its
findings were summarized in what has now come to stay as the celebrated
Newton’s law of uniform motion. Thus,
having a clear understanding of force and motion requires an adequate
understanding of these laws.
Inertia and the Newton First Law of
Uniform Motion
Uniform Motion
The first law has much to do about a quantity known as inertia. When a body is at rest, it has its tendency
to continue to remain in the state of rest.
This tendency is inertia. In the
same way, object in motion also has its tendency to continue its motion on a
straight line. This is also inertia.
to continue to remain in the state of rest.
This tendency is inertia. In the
same way, object in motion also has its tendency to continue its motion on a
straight line. This is also inertia.
Using the above, the inertia of a body hence is defined as the tendency
of a body at rest to continue to be in union on a straight line. The mass of a body is the measure of its
inertia ie the greater the mass of a body, the greater the force required to
change its states of rest or uniform motion.
The property of matter is called the inertia mass.
of a body at rest to continue to be in union on a straight line. The mass of a body is the measure of its
inertia ie the greater the mass of a body, the greater the force required to
change its states of rest or uniform motion.
The property of matter is called the inertia mass.
Newton first law of uniform motion is the summary of the above
explanation. The law states as follows
every object will continue in its present state of rest or uniform motion in a straight line , unless it is been acted upon by an
external force. The above provided the
force that causes motion, just like the concept of heat and temperature
explanation. The law states as follows
every object will continue in its present state of rest or uniform motion in a straight line , unless it is been acted upon by an
external force. The above provided the
force that causes motion, just like the concept of heat and temperature
Newton Second law of Uniform Motion
While the first law admits that
force causes motion, the second law sets out to describe the force that causes
motion. In doing this , a quantity known
as momentum is used. The mass of a body
and its velocity ie
force causes motion, the second law sets out to describe the force that causes
motion. In doing this , a quantity known
as momentum is used. The mass of a body
and its velocity ie
p= mass
x velocity
x velocity
where p is the momentum
Note
however that momentum can change since the velocity that is used in defining
momentum can change as well. Thus there
are
however that momentum can change since the velocity that is used in defining
momentum can change as well. Thus there
are
(I)
Initial momentum (p)
Initial momentum (p)
(II)
Final momentum (p)
Final momentum (p)
Where p1 = mu and P2
= mv, u and v are the initial and final velocity respectively.
= mv, u and v are the initial and final velocity respectively.
If m is the mass in kilogram (kg) and
u and v are the velocities in m/s then momentum will be kgm/s. Note that the
fact that momentum and change in momentum is used in describing forces that cause motion.
This as well has been explained by the Newton’s law of uniform motion which states as
follow:
u and v are the velocities in m/s then momentum will be kgm/s. Note that the
fact that momentum and change in momentum is used in describing forces that cause motion.
This as well has been explained by the Newton’s law of uniform motion which states as
follow:
F
α êp
α êp
t
Since êp p2
– p1
Since êp p2
– p1
(change
of momentum)
of momentum)
F α p2 – p1