Physics Lecture Review: Force and Motion

Flashcards covering key vocabulary, definitions, and concepts from the lecture on force, motion, and Newton's Laws.

Active Velocity

Calculated by timing how long it takes for a ball to travel a certain distance, used for further calculations.

Force

An interaction that has a direction and a magnitude, represented as a vector.

Unit Force (Imperial)

Pound.

Unit Force (SI)

Newton.

Mass

A measure of inertia, indicating how 'lazy' or resistant to change in motion an object is.

Newton's First Law of Motion

An object continues in a state of rest or in a state of motion at a constant speed along a straight line unless there is a force acting on it.

Net Force

The vector sum of all forces acting on an object.

Newton's Second Law of Motion

States that whenever there is a force, there is acceleration in that direction; expressed as Force vector = mass × acceleration (F = ma).

Newton (Derived Unit)

The force required to accelerate a one-kilogram mass at one meter per second squared (1 kg·m/s²).

Derived Units

Units constructed from basic fundamental units, like the Newton (from kilogram, meter, second).

Newton's Third Law of Motion

For every action, there is an equal and opposite reaction; forces come in pairs between interacting objects.

Free Body Diagram

A diagram used to identify and represent all forces acting on an isolated object of interest.

Universal Gravitation Law

States that every two particles with mass attract each other with a force proportional to the product of their masses and inversely proportional to the square of the distance between them (F = G(m1m2)/r²).

Gravitational Constant (g)

A combination of the universal gravitational constant, Earth's mass, and Earth's radius, resulting in approximately 9.8 m/s² for calculations of gravitational force on Earth's surface (Weight = mg).

Mass vs. Weight

Mass is the amount of 'stuff' in an object and remains constant, while weight is the gravitational pulling force on an object and can vary with location.

Fundamental Forces in Nature

Gravitational force, strong nuclear force, electromagnetic force, and weak nuclear force.

Gravitational Force

A fundamental force describing the attraction between any two particles with mass.

Strong Nuclear Force

A fundamental force that pulls the nucleus (protons and neutrons) together, acting over a very short range.

Electromagnetic Force

A fundamental force due to charge, acting over longer ranges; responsible for contact forces and tension.

Weak Nuclear Force

A fundamental force acting on a very short range.

Contact Force

Forces like pushing or pulling that result from direct contact between objects, electromagnetic in nature at the atomic scale.

Centripetal Force

A 'working force' directed towards the center of a circular path, required to keep an object in circular motion (e.g., tension in a string, gravity).

Normal Force

A contact force perpendicular to the surface of contact, pushing upward, often balancing gravity. It is a reaction force.

Friction Force

An electromagnetic contact force that resists relative motion between two surfaces due to microscopic interactions (roughness/asperities).

Force Addition (Parallelogram Law)

A method to sum two forces by constructing a parallelogram with the forces as adjacent sides; the diagonal represents the resultant force.

Force Addition (Triangular Law)

A method to sum forces by translating them head-to-tail; the resultant force is drawn from the tail of the first vector to the head of the last.