Explain Newton Second Law - Linear Motion

If objects only followed Newton's first law then everything would be traveling in straight lines at a constant velocity or at rest.  But we know that a lot of objects are at states in between these two.  Some objects are turning.  Others speed up or slow down.  This is because external forces are applied.

Newton's second law states the famous relationship:

The acceleration produced by a net force on a body is directly proportional to the magnitude of the net force, in the same direction as the net force.  The acceleration is inversely proportional to the mass of the body.

In other words:

F = ma

There are some big implications of this deceptively simple equation. 

Consider a Force and a mass:

• Twice as much force on an object produces twice as much acceleration.
• Twice as much mass with the same force will produce half as much acceleration.
• Three times as much force on three times as much mass is the same acceleration.