AP Physics 1 Flashcards: Rotational Equilibrium And Newtons First Law

What this deck covers

This deck focuses on Rotational Equilibrium And Newtons First Law, 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 happens to torque if the angle $\theta = 0^\text{o}$?

Answer: Torque is zero. Force parallel to radius produces no rotation.

Flashcard 2: Which direction does positive torque rotate an object?

Answer: Counterclockwise. Standard convention for positive rotation.

Flashcard 3: What is the condition for rotational equilibrium?

Answer: Net torque ($\tau_{\text{net}}$) must be zero. No angular acceleration occurs when forces balance.

Flashcard 4: Identify the variable representing angular displacement.

Answer: $\theta$. Symbol for angular position measurement.

Flashcard 5: Find the torque if $r = 3 \text{m}$, $F = 4 \text{N}$, $\theta = 90^\text{o}$.

Answer: $\tau = 12 \text{N·m}$. $\tau = 3 \times 4 \times \sin(90°) = 12$.

Flashcard 6: State the formula for moment of inertia of a point mass.

Answer: $I = m \times r^2$. Mass times distance squared from axis.

Flashcard 7: What is the condition for an object to be in static rotational equilibrium?

Answer: Net torque and net force must both be zero. No linear or rotational acceleration.

Flashcard 8: Which direction does negative torque rotate an object?

Answer: Clockwise. Standard convention for negative rotation.

Flashcard 9: If $\tau = 0$, what can be inferred about the object's rotation?

Answer: The object is either at rest or in uniform rotation. Newton's first law for rotation applies.

Flashcard 10: State the condition for equilibrium of a rotational system.

Answer: Sum of all external torques must be zero. Rotational equilibrium requires balanced torques.

Flashcard 11: What is the effect of torque on an object's rotational state?

Answer: Changes the object's angular velocity. Torque causes rotational acceleration or deceleration.

Flashcard 12: Identify the direction of the torque vector.

Answer: Perpendicular to the plane formed by $r$ and $F$. Right-hand rule determines direction.

Flashcard 13: What is the condition for equilibrium of a seesaw?

Answer: Sum of clockwise torques = Sum of counterclockwise torques. Torques must balance for equilibrium.

Flashcard 14: Find the net torque if $\tau_1 = 5 \text{N·m}$ and $\tau_2 = -3 \text{N·m}$.

Answer: Net torque = $2 \text{N·m}$. Vector sum: $5 + (-3) = 2$.

Flashcard 15: What is the relationship between torque and rotational inertia?

Answer: Torque causes rotational inertia to change angular velocity. Torque overcomes inertia to change motion.

Flashcard 16: Identify the symbol for angular velocity.

Answer: $\text{omega} (\text{ω})$. Greek letter representing angular velocity.

Flashcard 17: What happens to an object in rotational equilibrium if external torque is applied?

Answer: It will begin to rotate. Equilibrium breaks, causing angular acceleration.

Flashcard 18: What is the rotational analog of force in linear motion?

Answer: Torque ($\tau$). Rotational equivalent of linear force.

Flashcard 19: What is the rotational analog of mass?

Answer: Moment of inertia ($I$). Resistance to rotational motion.

Flashcard 20: State the formula for angular velocity.

Answer: $\text{Angular velocity} (\text{rad/s}) = \frac{\text{Change in angle}}{\text{Change in time}}$. Rate of angular position change.

Flashcard 21: Find the angular acceleration if $I = 2 \text{kg·m}^2$ and $\tau = 4 \text{N·m}$.

Answer: $\text{α} = 2 \text{rad/s}^2$. Using $\alpha = \tau/I = 4/2 = 2$.

Flashcard 22: State Newton's First Law in rotational form.

Answer: An object remains at rest or in uniform rotation unless acted upon by a net external torque. Rotational version of inertia law.

Flashcard 23: What is the formula for angular acceleration?

Answer: $\text{Angular acceleration} (\text{α}) = \frac{\text{Change in angular velocity}}{\text{Change in time}}$. Rate of angular velocity change.

Flashcard 24: How does increasing the force $F$ affect the torque?

Answer: Increases torque, if $r$ and $\theta$ remain constant. Torque is proportional to applied force.

Flashcard 25: Identify the unit of torque in SI units.

Answer: Newton-meter (N·m). Force times distance unit.

Flashcard 26: What is the significance of the angle $\theta$ in torque calculations?

Answer: Determines the component of force causing rotation. Only perpendicular force component creates torque.

Flashcard 27: What is torque's formula?

Answer: $\tau = r \times F \times \text{sin}(\theta)$. Force times perpendicular distance from axis.

Flashcard 28: What is the rotational kinetic energy formula?

Answer: $KE_{\text{rotational}} = \frac{1}{2} I \times \text{ω}^2$. Rotational analog of $\frac{1}{2}mv^2$.

Flashcard 29: Which quantity remains constant for an object in rotational equilibrium?

Answer: Angular velocity remains constant. No net torque means constant rotation.

Flashcard 30: What happens to angular velocity if net torque is applied?

Answer: Angular velocity changes. Net torque causes angular acceleration.