TOPIC
NAME
KINETICS OF PARTICLES AND THE
SECOND LAOW OF MOTIONS
Natasha Nicole C. Acao
ES 202 Dynamics of Rigid
Body
DATE
03/03/2023
KEY TERMS
Newton’s Second
Law of Motion
NOTES
Stated as follows: The acceleration of the body is directly
proportional to the net force acting on the body and inversely
proportional to the mass of the body.
• As the force acting upon an object is increased, the
acceleration of the object is increased.
∑ 𝐹 = 𝑚𝑎
•
•
•
Linear Momentum
of a Particle
∑ 𝐹 – sum or resultant of all the forces acting on a
particle.
m – mass
a – acceleration
Is a product of the mass (m) of an object and the velocity (v) of
the object. If an object has higher momentum, then it harder to
stop it.
𝑑
(𝑚𝑣)
𝑑𝑡
∑ 𝐹 – sum or resultant of all the forces acting on a
particle.
𝑑
(𝑚𝑣) – derivative of mv with respected to time (t).
𝑑𝑡
∑𝐹 =
•
•
System Units
SI System - is the metric system that is used universally as a
standard for measurements.
F = ma
N = kg m/s^2
Unit of:
F = Newton
m = kilogram
a = meter per second square
English System - a system of weights and measures based on
the foot and pound and second and pint.
F = ma
lb = slug ft/s^2
Unit of:
F = pound
m = slug
a = feet per second square
Therefore, uses unit analysis in order to convert from SI system
to English System and vice versa.
Equations of Motion
Rectangular Components
With rectangular coordinates in two dimensions, we will break
this single vector equation into two separate scalar equations. To
solve the equations, we simply break any given forces and
accelerations down into x and y components using sines and
cosines and plug those known values in. With two equations, we
should be able to solve for up to two unknown force or
acceleration terms.
∑Fx = m∗ax = m∗x
∑Fy = m∗ay=m∗y
Just as with a single dimension, the equations of motion are often
used in conjunction with the kinematics equations that relate
positions, velocities and accelerations. Depending on the
problem being examined, the kinematics equations may need to
be examined either before or after the kinetics equations.
Dynamic Equilibrium
Dynamic Equilibrium can be defined as the state of a given
system in which the reversible reaction taking place in it stops
changing the ratio of reactants and products, but there is a
movement of substances between the reactants and the
products. This movement occurs at an equal rate and there is no
net change of the reactant and product ratio.
Characteristics of Dynamic Equilibrium:
• This type of equilibrium is reversible in nature.
• This equilibrium implies that the reactants and the
products are still participating in chemical reactions.
• In dynamic equilibrium, the forward and the
backward reaction rates are equal
• It can only occur in closed systems
SUMMARY
Newton's second law is a quantitative explanation of the effects that a force can have on
a body's motion. It says that the temporal rate of change of a body's momentum is
identical in size and direction to the force applied to it. The link between forces and
motion is demonstrated by Newton's second law of motion, F=ma. It enables you to
compute the acceleration (and hence velocity and location) of an object subjected to
known forces.