Force and Acceleration

Any force that acts upon an object causes the object to move, or more appropriately, accelerate. An apple falling from a tree (the force) hits a basket ball (the object) and the basketball begins to move faster and faster (acceleration), until it loses the acceleration and slows down.

Considering the ball has a mass of 1kg (mass is an objects weight on Earth less its gravity). Then the acceleration of the ball is measured by its speed per unit of time.

Newton Unit

With this in mind, 1 Newton (N) is equal to an object with a mass of one kilogram (1kg) moving at a speed of one meter per second each second.

1 N =  (1m/sec²) or simply put, 1 Newton = Mass x Acceleration

The Newton represents the force on an object or the work done, referred as the energy times the distance the force moves.

Units of newtons have no relative association to the real world, unless we add a distance factor; that is, unless we can describe how far this force has accelerated over a certain distance.  Enter the Joule.


1 joule is a unit of energy (or work done) that equates to a mass of 1 kg that is accelerating at 1 meter / second over 1 a distance of 1 meter. A more specific way to describe a joule is N times meters.

J = N x M, or simply put, 1 Joule = (Mass x Acceleration) x (distance).

If we lift our 1kg basketball 1 meter, we have 1 joule.

To gain more perspective on Joules, please view this video


1 watt is equal to 1 joule / second or 1 kg that has moved a distance of 1 meter at a velocity of 1 meter / second squared for 1 second.

Reverting back to the apple example, if the basketball of mass 1 kg is moving at 1 meter/second over a distance of 1 meter (joule) and it did this in 1 second, we have a watt. Another example would be moving 1 lb about 9 inches.


1 erg =  10−7 joules or 10 over 7 zeroes.

An example would be the sun’s luminosity (brighness) is equal to 3.846×1026 W or 3.9 x 10 33 ergs/sec.

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