Mechanical Equilibrium

net force

the combination of all forces acting on an object

resultant

the sum of two or more vectors

support force

the upward force that balances the weight of an object on a surface

equilibrium rule

whenever the net force of an object is zero, the object is said to be in mechanical equilibrium

How can you change an object's state of motion?

A force is needed to change an object's state of motion.

How are static and dynamic equilibrium different?

Objects at rest are said to be in static equilibrium; objects moving at constant speed in a straight-line path are said to be in dynamic equilibrium.

For an object at rest on a horizontal surface, what must the support force be equal to?

For an object at rest on a horizontal surface, the support force must equal the object's weight.

How can you find the resultant of two vectors?

To find the resultant of two non-parallel vectors, constructs a parallelogram wherein the two vectors are adjacent sides. The diagonal of the parallelogram shows the resultant.

How can you express the equilibrium rule mathematically?

You can express the equilibrium rule mathematically as ∑F = 0.

force

a push or a pull

scalar quantity

a quantity that can be described by magnitude only, and has no direction

a vector quantity

a quantity that needs both magnitude and direction for a complete description

mechanical equilibrium

a state wherein no physical changes occur

vector

an arrow that represents the magnitude and direction of a quantity