What is force?
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In physics, force is a push or pull on an object.
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A force can cause an object to accelerate, slow down, remain in place, or change shape.
How to Measure Force?
The unit of measure for force is the newton which is abbreviated as "N". One newton is the force needed to accelerate one gram of mass by one centimeter per second squared. Other units of force include the dyne and the pound-force.
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Force, Mass, and Acceleration
Force can be figured out if you know the mass and acceleration of an object. This equation comes from Newton's Second Law of Motion:
f = m * a
Where f = force, m = mass, and a = acceleration.
Force, Mass, and Acceleration
Force can be figured out if you know the mass and acceleration of an object. This equation comes from Newton's Second Law of Motion:
f = m * a
Where f = force, m = mass, and a = acceleration.
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Force not only has a magnitude (which is what we get in newtons when we use the equation above), but it also has a direction. This makes force a vector.
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Vectors are shown by an arrow that indicates the direction of the force and a number that indicates the magnitude. See the pictures to the right to see how the arrow is used to show the direction of the force.
Forces and Vectors
Forces in Equilibrium
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Sometimes there can be many forces acting on an object, but the object remains still. In this case the forces are in equilibrium. The sum of the forces, or the net force, is zero.
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The picture shows an object sitting on a table. The object isn't moving. This is because the force of gravity pulling the object down is equal and opposite to the force of the table pushing up. The net force is zero and the forces are in equilibrium.​
