Unit 4: Momentum and Collisions

Vocabulary flashcards covering core physics concepts from Unit 4: Momentum, including impulse, conservation laws, collision types, and the egg drop challenge criteria.

Egg Drop Challenge

A challenge to design a protective contraption that minimizes the force an egg experiences when dropped from heights up to $5.5\,\text{m}$, where ties are decided by lower mass and the egg must be inserted and removed within $20\,\text{seconds}$.

Momentum ($p$)

The amount of impact an object has when it collides, which accounts for direction, is calculated as $p = m v$, and is measured in units of $\text{kg}\cdot\text{m/s}$.

Impulse ($J$)

The total amount of force an object experiences during a collision, calculated by the formula $J = F_{net} \cdot t$ and measured in $\text{N}\cdot\text{s}$.

Impulse-Momentum Theorem

The principle stating that the impulse experienced by an object equals its change in momentum, represented by the equation $F_{net} \cdot t = m v_f - m v_i$.

Methods to Reduce Collision Force ($F_{net}$)

Three ways to manipulate force based on the impulse-momentum theorem: reducing the difference between final and initial velocity ($v_f - v_i$), reducing the mass of the object, or increasing the collision time ($t$).

Collision

An event that occurs when two objects strike each other, during which the impulse-momentum theorem applies to both objects.

Newton's Third Law in Collisions

The principle establishing that when two objects collide, the forces they exert on each other must be equal in magnitude and opposite in direction, and the contact time ($t$) must also be equal.

Conservation of Momentum

The law stating that the total momentum of objects in a closed system before and after a collision must be the same: $m_1 v_{1f} + m_2 v_{2f} = m_1 v_{1i} + m_2 v_{2i}$.

Elastic Collision

A collision type where no damage occurs and objects cleanly bounce off each other, characterized by an elasticity of $100\%$.

Inelastic Collision

A collision type where colliding objects cause damage to each other but do not stick together, characterized by an elasticity between $0\%$ and $100\%$ ($0\% < \text{Elasticity} < 100\%$).

Perfectly Inelastic Collision

A collision type where the colliding objects stick together after impact, characterized by an elasticity of $0\%$.