Newton's Second Law,

F = ma

In the presence of a NET FORCE, an object experiences an ACCELERATION

 

• directly proportional to the NET FORCE

   

• inversely proportional to the MASS of the object.

Remember, though,

 

• F is the NET force

   

• m is the mass which that net force acts on.

 

We often turn this around and write it as

What are the UNITS of force in

F = m a

A force of ONE unit

will give an object of 1.0 kg mass

an acceleration of 1.0 m/s/s ;

this force is known as

ONE NEWTON (1.0 N) .

1 N = ( 1 kg ) ( 1 m/s/s )

 

F = m a

Force will be measured in newtons

A force of 1 N will give

a mass of 1 kg

an accelertion of 1 m/s/s.

1 N = ( 1 kg ) ( 1 m/s/s )

	12 N = ( 3 kg ) ( 4 m/s/s ) A force of 12 N could give a mass of 3 kg an accelertion of 4 m/s/s
	12 N = ( 2 kg ) ( 6 m/s/s ) A force of 12 N could give a mass of 2 kg an accelertion of 6 m/s/s .

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If an object is in equilibrium -- at rest -- then, the net force on the object must be zero.

That is, the sum of all the forces on an object is zero when the object is in equilibrium.

Mass			Weight
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(c) 2005, Doug Davis; all rights reserved