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 effect on $L$ if $\omega$ quadruples and $I$ is constant?

Answer: $L$ quadruples. Angular momentum is proportional to angular velocity.

Flashcard 2: What happens to $L$ when radius doubles but mass and velocity remain constant?

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

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

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

Flashcard 5: Identify the relationship between torque and angular impulse.

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

Flashcard 6: 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 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: State the formula for angular impulse.

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

Flashcard 9: Calculate $L$ for a $2\,\text{kg}$ mass at $3\,\text{m/s}$, $r=4\,\text{m}$.

Answer: $L = 24 \text{kg}\cdot\text{m}^2/\text{s}$. Using $L = mvr$: $2 \times 3 \times 4 = 24$.

Flashcard 10: 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 11: 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 12: What is the unit of angular momentum in SI units?

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

Flashcard 13: 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 14: 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 15: What is the moment of inertia for a thin ring?

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

Flashcard 16: 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 17: What is the unit of angular momentum in SI units?

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

Flashcard 18: Find the change in angular momentum given torque $\tau$ and time $t$.

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

Flashcard 19: 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 20: 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 21: What is the moment of inertia for a point mass?

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

Flashcard 22: 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 23: 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 24: What is the conservation law for angular momentum?

Answer: Total angular momentum is constant if no external torque acts. No net external torque means angular momentum stays constant.

Flashcard 25: 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 26: Define angular momentum for a rotating rigid body.

Answer: $L = I \omega$. Fundamental definition for rigid body rotation.

Flashcard 27: What is the moment of inertia for a thin ring?

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

Flashcard 28: What is the formula for angular momentum of a particle?

Answer: $L = r \times p = r \times mv$. Cross product of position vector and linear momentum.

Flashcard 29: Which equation represents the relationship between torque and angular acceleration?

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

Flashcard 30: Calculate the torque for $r=2\,\text{m}$, $F=10\,\text{N}$, $\theta=90\deg ree$.

Answer: $\tau = 20 \text{Nm}$. Using $\tau = rF\sin(90°)$: $2 \times 10 \times 1 = 20$.

Flashcard 31: Which equation represents the angular impulse-momentum theorem?

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

Flashcard 32: 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 33: What effect does doubling $m$ have on $L$ if $r$ and $v$ are constant?

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

Flashcard 34: How does angular momentum change with increasing rotational speed?

Answer: Angular momentum increases. Angular momentum is proportional to angular velocity.

Flashcard 35: 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 36: Which equation represents the angular impulse-momentum theorem?

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

Flashcard 37: 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 38: What is the conservation law for angular momentum?

Answer: Total angular momentum is constant if no external torque acts. No net external torque means angular momentum stays constant.

Flashcard 39: 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 40: What is the effect on $L$ if $\omega$ quadruples and $I$ is constant?

Answer: $L$ quadruples. Angular momentum is proportional to angular velocity.

Flashcard 41: Which equation represents the relationship between torque and angular acceleration?

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

Flashcard 42: What effect does doubling $m$ have on $L$ if $r$ and $v$ are constant?

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

Flashcard 43: Calculate $L$ for a $2\,\text{kg}$ mass at $3\,\text{m/s}$, $r=4\,\text{m}$.

Answer: $L = 24 \text{kg}\cdot\text{m}^2/\text{s}$. Using $L = mvr$: $2 \times 3 \times 4 = 24$.

Flashcard 44: Which quantity remains constant in an isolated system with no external torque?

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

Flashcard 45: 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 46: 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 47: 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 48: What is the symbol for angular momentum?

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

Flashcard 49: What is the moment of inertia for a point mass?

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

Flashcard 50: How does angular momentum change with increasing rotational speed?

Answer: Angular momentum increases. Angular momentum is proportional to angular velocity.

Flashcard 51: What is the primary cause of a change in angular momentum?

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

Flashcard 52: State the formula for angular impulse.

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

Flashcard 53: Calculate the torque for $r=2\,\text{m}$, $F=10\,\text{N}$, $\theta=90\deg ree$.

Answer: $\tau = 20 \text{Nm}$. Using $\tau = rF\sin(90°)$: $2 \times 10 \times 1 = 20$.

Flashcard 54: What happens to $L$ when radius doubles but mass and velocity remain constant?

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

Flashcard 55: What happens to $L$ if the direction of velocity is reversed?

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

Flashcard 56: 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 57: 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 58: Find the change in angular momentum given torque $\tau$ and time $t$.

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

Flashcard 59: 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 60: Which quantity remains constant in an isolated system with no external torque?

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

Flashcard 61: 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 62: 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 63: Define angular momentum for a rotating rigid body.

Answer: $L = I \omega$. Fundamental definition for rigid body rotation.