Unit 2 Motion and Force Vocabulary

Vocabulary practice flashcards covering fundamental physical concepts including motion, speed, velocity, acceleration, forces, Newton's Laws, friction, momentum, and graph interpretations.

Motion

The state that occurs when an object changes its position relative to a reference point.

Reference Point

An indicator, location, or object used to determine whether something has moved, serving as the basis from which position is measured, recorded, or observed.

Distance

The total length of the entire path traveled by an object ($d$).

Displacement

The distance and direction of an object's change in position from its starting point to its ending point.

Speed

The rate at which an object covers distance per unit time ($s = \frac{d}{t}$), without specifying direction.

Average Speed

The total distance traveled divided by the total time taken ($\text{Average speed} = \frac{\text{total distance}}{\text{total time}}$).

Instantaneous Speed

The exact speed of an object at one specific, given moment in time, such as the reading displayed on a speedometer.

Velocity

The speed of an object in a specified direction of motion ($v = \frac{d}{t}$ plus direction).

Acceleration

The rate at which velocity changes over time ($a = \frac{v_f - v_i}{t}$ or $a = \frac{\Delta v}{\Delta t}$), occurring when an object speeds up, slows down, or changes direction.

Force

A push or pull exerted on an object that can change its motion.

Net Force

The overall or total sum of all forces acting on an object after all individual forces are combined.

Balanced Forces

Forces acting on an object that are equal in size and opposite in direction, resulting in a net force of $0\,N$ and causing no change in motion.

Unbalanced Forces

Forces acting on an object that are not equal and opposite, producing a non-zero net force that causes the object to accelerate in the direction of the net force.

Inertia

The tendency of an object to resist any change in its motion, which depends directly on the mass of the object.

Newton's 1st Law (Law of Inertia)

States that an object at rest stays at rest, and an object moving at a constant velocity continues moving at that velocity, unless acted upon by an unbalanced net force.

Newton's 2nd Law

States that a net force acting on an object causes it to accelerate in the direction of the net force, calculated using $F = m \times a$.

Newton's 3rd Law

States that when one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object (every action force has an equal and opposite reaction force).

Friction

A force that opposes motion when two surfaces rub together or come into contact with one another.

Static Friction

The frictional force between two touching surfaces that are not moving relative to each other.

Sliding Friction

The frictional force that opposes the motion of two surfaces sliding past one another.

Rolling Friction

The frictional force acting between a rolling object and the surface it rolls upon.

Air Resistance

A force exerted by air that opposes the motion of an object traveling through it, affected by the object's size, shape, and speed.

Terminal Velocity

The maximum velocity reached by a falling object when the upward force of air resistance balances the downward force of gravity, yielding a net force of $0\,N$ and zero acceleration.

Law of Universal Gravitation

States that every mass attracts every other mass in the universe, where larger masses yield a stronger force and greater distances yield a weaker force ($F = G \frac{m_1 m_2}{r^2}$).

Weight

The measure of the gravitational force acting on an object's mass ($W = F = m \times a = m \times 9.8\,m/s^2$).

Law of Conservation of Momentum

States that the total momentum of a closed system remains constant unless acted upon by an outside force; momentum is transferred during collisions rather than created or destroyed.

Slope of a Distance vs. Time Graph

The numerical rate of change on a distance vs. time graph ($d$ vs. $t$), which represents the object's speed.

Slope of a Velocity vs. Time Graph

The numerical rate of change on a velocity vs. time graph ($v$ vs. $t$), which represents the object's acceleration.