PHY 1510 – Introduction to Newtonian Mechanics: Dynamics and Forces

This set of vocabulary flashcards defines the primary forces, Newton's three laws of motion, and related mechanical concepts from the PHY 1510 dynamics unit.

Gravitational force

A force that pulls objects downward with a magnitude of $mg$ and direction denoted as $\vec{F}_g$ or $\vec{W}$. In free fall, the acceleration is $a = -g = -9.8\,m/s^2$.

Normal force

A contact force ($\vec{N}$ or $\vec{F}_N$) exerted by a solid surface that pushes on objects perpendicular to the surface to resist them passing through.

Frictional force

A force ($\vec{f}$ or $\vec{F}_f$) that occurs when one object slides or attempts to slide over another, directed along the surface and opposite to the direction of intended motion.

Static friction

A force that can have any magnitude from $0\,N$ up to a maximum; once this maximum is reached, the object starts to slide. It can be calculated using Newton’s 2nd Law.

Kinetic friction

A force that resists motion when an object is sliding. It is generally smaller than the maximum static frictional force and has only one value.

Spring force

A force ($\vec{F}_{sp}$) that can push or pull, where the magnitude increases the longer the spring is stretched or compressed.

Tension

A force ($\vec{F}_T$) exerted by a rope pulled on an object; it is the same everywhere inside a rope.

Contact forces

Forces that require physical contact between the agent and the object for the force to be applied.

Long-range forces

Forces that act over a distance without requiring physical contact, such as gravity.

Superposition of forces

The principle that the vector sum of a bunch of forces acting on an object is the net force.

Newton’s 1st Law

If no net force acts on a body ($F_{net} = 0$), the body’s velocity cannot change, meaning it cannot accelerate. A body at rest stays at rest, and a moving body continues with the same velocity.

Newton’s 2nd Law

The law stating that a net force causes an object to accelerate, represented by the equations $\vec{a} = \frac{\vec{F}<em>{net}}{m}$ and $\vec{F}</em>{net} = m\vec{a}$.

Newton’s 3rd Law

The principle that if body A exerts a force on body B, body B exerts a force of equal magnitude but opposite direction on body A ($\vec{F}<em>{A \text{ on } B} = -\vec{F}</em>{B \text{ on } A}$).

Hooke’s Law

The formula $F = -k \Delta x$ describing the force exerted by a spring, where $k$ is the spring constant and $\Delta x$ is the displacement relative to the equilibrium position.

Newton (N)

The unit of force, defined as $1\,N = 1\,kg \cdot m/s^2$.

Mass

An intrinsic property of an object that is independent of where it is measured, used in Newton’s 2nd Law to determine acceleration.

Centripetal force

A force named after its effect in circular motion; it is not a new type of force, but rather a role played by different forces (like gravity or tension) in specific scenarios.