AP Physics 1 Flashcards: Angular Momentum And Angular Impulse

What this deck covers

This deck focuses on Angular Momentum And Angular Impulse, giving you a quick way to review the definitions, rules, and examples that matter most for AP Physics 1.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is the symbol for angular momentum?

Answer: $L$. Standard symbol for angular momentum in physics.

Flashcard 2: What is the moment of inertia for a point mass?

Answer: $I = mr^2$. All mass concentrated at distance $r$ from axis.

Flashcard 3: What is the formula for torque in terms of force and lever arm?

Answer: $\tau = rF\sin(\theta)$. Force times perpendicular distance from axis.

Flashcard 4: Which equation represents the relationship between torque and angular acceleration?

Answer: $\tau = I\alpha$. Newton's second law for rotational motion.

Flashcard 5: What is the angular momentum of a solid sphere rotating at angular velocity $\omega$?

Answer: $L = I \omega = \frac{2}{5}mr^2 \omega$. Uses the solid sphere moment of inertia formula.

Flashcard 6: Which equation represents the relationship between torque and angular acceleration?

Answer: $\tau = I\alpha$. Newton's second law for rotational motion.

Flashcard 7: What is the effect of increasing $r$ on $L$ if $v$ is constant?

Answer: $L$ increases. Angular momentum proportional to radius for fixed velocity.

Flashcard 8: What is the angular momentum of a rotating rod about its center?

Answer: $L = \frac{1}{12}mL^2 \omega$. Uses rod's moment of inertia about center.

Flashcard 9: State the formula for the moment of inertia of a solid sphere.

Answer: $I = \frac{2}{5}mr^2$. Standard moment of inertia for solid sphere.

Flashcard 10: What is the moment of inertia for a point mass?

Answer: $I = mr^2$. All mass concentrated at distance $r$ from axis.

Flashcard 11: What is the angular momentum of a disk rotating at $\omega$ with mass $m$ and radius $r$?

Answer: $L = \frac{1}{2}mr^2 \omega$. Uses disk moment of inertia formula.

Flashcard 12: What is the formula for angular acceleration $\alpha$ in terms of $\omega$ and $t$?

Answer: $\alpha = \frac{\Delta \omega}{\Delta t}$. Rate of change of angular velocity.

Flashcard 13: What is the effect of external torque on a system's angular momentum?

Answer: It changes the angular momentum. Torque causes angular momentum to change over time.

Flashcard 14: Calculate $L$ for a $1\,\text{kg}$ mass moving at $2\,\text{m/s}$, $r=1\,\text{m}$.

Answer: $L = 2 \text{kg}\cdot\text{m}^2/\text{s}$. Using $L = mvr$: $1 \times 2 \times 1 = 2$.

Flashcard 15: Which equation represents the angular impulse-momentum theorem?

Answer: $J = \Delta L$. Angular impulse equals change in angular momentum.

Flashcard 16: Which quantity remains constant in an isolated system with no external torque?

Answer: Angular momentum. Conserved quantity in isolated rotational systems.

Flashcard 17: State the moment of inertia for a solid cylinder.

Answer: $I = \frac{1}{2}mr^2$. Standard formula for solid cylinder rotating about its axis.

Flashcard 18: What effect does doubling $m$ have on $L$ if $r$ and $v$ are constant?

Answer: $L$ doubles. Angular momentum is proportional to mass.

Flashcard 19: Calculate the angular impulse given $\tau=5\,\text{Nm}$ and $t=3\,\text{s}$.

Answer: Angular impulse = $15 \text{Nm}\cdot\text{s}$. Simple multiplication: $5 \times 3 = 15$.

Flashcard 20: What is the unit of angular momentum in SI units?

Answer: kg·m²/s. Combines mass (kg), length squared (m²), and time (s).

Flashcard 21: Find the change in angular momentum given torque $\tau$ and time $t$.

Answer: $\Delta L = \tau \times t$. Angular impulse-momentum theorem application.

Flashcard 22: What is the formula for torque in terms of force and lever arm?

Answer: $\tau = rF\sin(\theta)$. Force times perpendicular distance from axis.

Flashcard 23: State the formula for angular impulse.

Answer: $J = \tau \times \text{time}$. Angular impulse equals torque multiplied by time duration.

Flashcard 24: What is the moment of inertia for a thin ring?

Answer: $I = mr^2$. All mass at distance $r$ from rotation axis.

Flashcard 25: What is the formula for angular velocity $\omega$ in terms of period $T$?

Answer: $\omega = \frac{2\pi}{T}$. Relates angular velocity to rotational period.

Flashcard 26: How is angular velocity related to angular momentum?

Answer: Angular momentum = Moment of inertia × Angular velocity. Angular momentum equals moment of inertia times angular velocity.

Flashcard 27: What happens to $L$ when radius doubles but mass and velocity remain constant?

Answer: $L$ doubles. Angular momentum is proportional to radius.

Flashcard 28: Identify the relationship between torque and angular impulse.

Answer: Angular impulse = Torque × Time. Angular impulse is the product of torque and time.

Flashcard 29: What happens to $L$ if the direction of velocity is reversed?

Answer: $L$ reverses direction. Angular momentum is a vector quantity.

Flashcard 30: What is the primary cause of a change in angular momentum?

Answer: External torque. Torque is the rotational analog of force.