1.6 Momentum IGCSE Physics Flashcards

Vocabulary-style flashcards covering momentum definitions, calculations, conservation principles, and the relationship between force, time, and impulse based on IGCSE Physics notes.

Momentum

A vector quantity possessed by an object with mass that is in motion. It keeps an object moving in the same direction and is calculated as the product of mass and velocity.

Vector Quantity (Momentum context)

The property that requires direction to be taken into account when calculating momentum, meaning it can be positive or negative depending on the direction of travel.

Momentum Formula

$p = mv$, where $p$ is momentum in $kg\,m\,s^{-1}$, $m$ is mass in $kg$, and $v$ is velocity in $m\,s^{-1}$.

Conditions for Change in Momentum

Momentum will change if an object accelerates or decelerates (velocity changes), if it changes direction, or if its mass changes.

Principle of Conservation of Momentum

The principle stating that in a closed system, the total momentum before a collision is equal to the total momentum after the collision.

Closed System

A system where the energy remains constant and there is an absence of external forces, such as friction.

Conservation Equation (Separate Objects)

$m_1u_1 + m_2u_2 = m_1v_1 + m_2v_2$, used when two objects move separately both before and after a collision.

Conservation Equation (Sticking Together)

$m_1u_1 + m_2u_2 = (m_1 + m_2)v$, used when two objects move separately before a collision but stick together after the collision.

Impulse

A term that quantifies the overall effect of a force acting over time; it is the overall change in momentum that an object experiences.

Impulse Formulas

$Impulse = F\Delta t$ and $Impulse = \Delta p = mv - mu$, measured in units of $Ns$ or $kg\,m\,s^{-1}$.

Force (in terms of Momentum)

The rate of change of momentum on a body, expressed as $F = \frac{\Delta p}{\Delta t}$ or $F = \frac{mv - mu}{\Delta t}$.

Force and Momentum Relationship

Force and change in momentum are directly proportional; as the change in momentum increases, the force exerted also increases.

Force and Time Relationship

Force and time are inversely proportional; as the time in contact during a collision increases, the force exerted decreases.

Car Safety Features (e.g., Airbags)

Features designed to increase the amount of time it takes for a passenger's momentum to become zero, thereby reducing the amount of force the passenger experiences during a collision.