Motion and Dynamics in Physics
Motion
Superposition
When a mobile body is subjected to two simultaneous movements, the kinematic variables (position, velocity, and acceleration) are obtained by adding the kinematic variables of the two movements.
Principle of Independence
When a mobile body’s motion is composed of two simple movements, its position at a given time is independent of how the simple movements operate, whether simultaneously or successively.
Parabolic Motion
Parabolic motion is composed of one rectilinear uniform motion and one uniformly accelerated rectilinear motion, perpendicular to each other.
Reach
Reach is the vertical distance, above ground, from the launch point to the impact point.
Periodic Motions
Periodic motions are those in which the kinematic variables (position, velocity, and acceleration) take the same values from time to time, t, called the period of motion.
Frequency
Frequency is the number of times a motion repeats in a given time. It is measured in Hertz (Hz = s-1).
Uniform Circular Motion (MCU)
Uniform circular motion is a movement whose trajectory is the circumference of a circle and the velocity remains constant.
Simple Harmonic Motion (+)
Simple harmonic motion is the movement of the projection of a mobile body that follows a uniform circular motion with angular velocity, ω, in a circumference of radius a.
Dynamics
Dynamics is the branch of physics that studies the causes of changes in motion.
Newton
The Newton is the unit of force in the SI. It is the force applied to a body of mass 1 kg to give it an acceleration of 1 m/s2.
Effects of Forces on Bodies
- Change the state of motion of bodies.
- Deform bodies.
Gravitational Interaction
Any two bodies exert gravitational forces on each other. The value of these forces is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. The direction of interaction is along the line connecting the bodies, and the force is always attractive.
Principle of Inertia (Newton’s First Law)
A free body, i.e., a body on which no force is acting or the sum of the forces acting on it is zero, is at rest or moving with uniform rectilinear motion.
Inertia or Inertial Mass
Inertia or inertial mass is a property of matter that measures its resistance to changing its state of motion.
Fundamental Principle (Newton’s Second Law)
This principle states that force is proportional to mass and acceleration.