Isaac Newton

Isaac Newton was an English physicist and mathematician, born on January 4, 1643, in Woolsthorpe, Lincolnshire, England.

Newton was enrolled at the King's School in Grantham, a town in Lincolnshire, where he lodged with a local apothecary and was introduced to the interesting world of chemistry.

Isaac Newton made discoveries in optics, motion and mathematics. Newton theorized that white light was a composite of all colors of the spectrum, and that light was composed of particles. His momentous book on physics, "Principia", contains information on nearly all of the essential concepts of physics except energy, ultimately helping him to explain the laws of motion and the theory of gravity.

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Legend has it that, between 1665 and 1667, when Newton returned home from Trinity College, he experienced his famous inspiration of gravity with the falling apple. According to this common myth, Newton was sitting under an apple tree when a fruit fell and hit him on the head, inspiring him to suddenly come up with the theory of gravity.

Sir Isaac Newton died in his sleep in London, on 20 March 1727.

Isaac Newton's Laws of Motion

Newton's Laws of Physics

In 1687, Isaac Newton published "Philosophiae Naturalis Principia Mathematica" (Mathematical Principles of Natural Philosophy), most often known as "Principia".

Principia offers an exact quantitative description of bodies in motion, with three basic, but important laws of motion:

Newton's First Law: Inertia

An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line, unless acted on by an unbalanced force.

Examples of inertia involving aerodynamics, according to NASA:

The motion of an airplane when a pilot changes the throttle setting of an engine.

The motion of a ball falling down through the atmosphere.

A model rocket being launched up into the atmosphere.

The motion of a kite when the wind changes.

Newton's Second Law: Acceleration

The acceleration of an object depends on the mass of the object and the amount of force applied.

Example of force involving aerodynamics (NASA):

An aircraft's motion resulting from aerodynamic forces, aircraft weight, and thrust.

Newton's Third Law: Action and Reaction

Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first.

Examples of action and reaction involving aerodynamics (NASA):

The motion of lift from an airfoil, the air is deflected downward by the airfoil's action, and in reaction, the wing is pushed upward.

The motion of a spinning ball, the air is deflected to one side, and the ball reacts by moving in the opposite.

The motion of a jet engine produces thrust and hot exhaust gases flow out the back of the engine, and a thrusting force is produced in the opposite direction.

Reasoning Exercises - Types