Can moving objects be in equilibrium?

EQUILIBRIUM

• We have seen that objects in Physics fall into two categories: those that are in equilibrium, and those that are not in equilibrium.

EQUILIBRIUM

• We have seen that objects in Physics fall into two categories: those that are in equilibrium, and those that are not in equilibrium;

• We have seen that objects will remain in equilibrium in the absence of a (Physics) agent;

EQUILIBRIUM

• We have seen that objects in Physics fall into two categories: those that are in equilibrium, and those that are not in equilibrium;

• We have seen that objects will remain in equilibrium in the absence of a (Physics) agent;

• Objects will be out of balance during the time the agent is acting on it.

EQUILIBRIUM

In equilibrium• No outside agent

• Motion is due to INERTIA

Out of equilibrium• Outside agent

• Motion is due to IMPULSE

ONCE UPON A TIME…

…scientists believed that all objects in motion where being acted upon by an agent.They called this agent “impetus”:

IMPETUS MOTION

IMPETUS MOTION

GALILEO GALILEI

• He presented a logic “thought experiment” to prove that objects can move without an agent present.

• He concluded from his experiments that objects moving at a constant velocity (speed + a direction) are also in equilibrium.

MOTION @ CONSTANT UNIFORMVELOCITY MOTION

GALILEO GALILEI

MOTION @ CONSTANT UNIFORMVELOCITY MOTION

AND

UNIFORM BALANCED MOTION STATE

The Second Simplest State

Identifier(s)• Object in constant velocity.

Physics Concept(s)• DYNAMIC EQUILIBRIUM

The Second Simplest State

Identifier(s)• Object in constant velocity. Motion Type: UNIFORM

Physics Concept(s)• DYNAMIC EQUILIBRIUM in MOTION

The Second Simplest State

Identifier(s)• Object in constant velocity. Motion Type: UNIFORM

• 2 types

Physics Concept(s)• DYNAMIC EQUILIBRIUM in MOTION

The Second Simplest State

Identifier(s)• Object in constant velocity. Motion Type: UNIFORM

• 2 types

Physics Concept(s)• DYNAMIC EQUILIBRIUM in MOTION

• Rotational (object rotates)

The Second Simplest State

Identifier(s)• Object in constant velocity. Motion Type: UNIFORM

• 2 types

Physics Concept(s)• DYNAMIC EQUILIBRIUM in MOTION

• Rotational (object rotates)

• Translational (motion on a line)

INERTIA

• Ability for an object to sustain its state of equilibrium indefinitely.

• For objects in UNIFORM MOTION, the measure of the object’s inertia is the object’s MOMENTUM.

PHYSICS CONCEPT MEASURE “MOVING” INERTIA MOMENTUM

MOMENTUM

• 2 types (ROTATIONAL and TRANSLATIONAL)

• ROTATIONAL is called ANGULAR MOMENTUM

• TRANSLATIONAL is called LINEAR MOMENTUM

LINEAR MOMENTUM

• To find the amount of an object’s linear momentum, multiply its mass by its speed.

• Momentum = mass X speed