AP Physics 1: Force and Systems Dynamics

What is a System in dynamics problems?

A collection of objects that you choose to analyze as a single unit or distinct entities.

What does 'System Boundary' refer to?

An imaginary line separating the system from the environment.

What are Internal Forces?

Forces between objects within the system that usually cancel out.

What are External Forces?

Interactions crossing the system boundary that cause acceleration.

What is the Center of Mass?

The unique point where the weighted relative position of the distributed mass sums to zero.

How does the Center of Mass behave under a net external force?

It follows a simple parabolic trajectory, acting as if all mass were concentrated at that point.

Define a Force as it pertains to motion.

A vector interaction between two objects that can cause a change in motion (acceleration).

What is Gravitational Force?

A field force attracting objects with mass toward the Earth's center.

What does Normal Force do?

It's a contact force perpendicular to the surface that prevents objects from passing through each other.

What is Tension in physics?

A pulling force transmitted axially through a string, cable, or rope.

How is Friction defined?

A resistive contact force parallel to the surface, opposing the direction of relative motion.

What does Applied Force refer to?

A generic push or pull acting on an object.

What is a Free-Body Diagram (FBD)?

A visual representation used to analyze forces acting on an object.

What is a key rule for drawing Free-Body Diagrams?

Represent the object as a dot or a simple box and draw forces as arrows from the center outward.

What does Newton's Third Law state?

For every action, there is an equal and opposite reaction.

What is the Law of Inertia?

An object at rest stays at rest, and an object in motion stays in motion with constant velocity unless acted on by a net external force.

Define Inertia.

The property of an object to resist changes in its state of motion.

What happens when the net force is zero?

The object is in equilibrium.

What is Newton's Second Law?

The acceleration of a system is directly proportional to the net external force and inversely proportional to the system's mass.

What does
ightarrow a = \frac{\Sigma \vec{F}}{m} represent?

The equation that relates acceleration to net force and mass.

What is the mass in F=ma when treating multiple objects as one system?

The total mass of all moving parts.

What is a common mistake related to Free-Body Diagrams?

Drawing components on the FBD, which is considered double counting the force.

Why are Normal Force and Tension considered 'smart' forces?

They only exert as much force as necessary to maintain constraints.

What is Static Equilibrium?

When an object is at rest with zero net force and acceleration.

What is Dynamic Equilibrium?

When an object moves at a constant velocity with zero net force.

What principle governs the relationship between force and the motion of an object?

Newton's Second Law.