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: State the principle of superposition for torques.

Answer: The net torque is the vector sum of all individual torques. Individual torques add vectorially.

Flashcard 2: 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 3: 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 4: 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 5: Identify the formula for the lever arm.

Answer: Lever arm $= r \times \text{sin}(\theta)$. Perpendicular distance from force line to axis.

Flashcard 6: 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 7: 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 8: What happens to angular velocity if net torque is applied?

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

Flashcard 9: State the relationship between torque and angular acceleration.

Answer: $\tau = I \times \alpha$. Newton's second law for rotation.

Flashcard 10: What happens to angular velocity if net torque is applied?

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

Flashcard 11: 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 12: If moment of inertia increases, what happens to angular acceleration?

Answer: Angular acceleration decreases. From $\tau = I\alpha$, larger $I$ means smaller $\alpha$.

Flashcard 13: Identify the formula for the lever arm.

Answer: Lever arm $= r \times \text{sin}(\theta)$. Perpendicular distance from force line to axis.

Flashcard 14: Identify the direction of the torque vector.

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

Flashcard 15: Identify the symbol for angular velocity.

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

Flashcard 16: State the principle of superposition for torques.

Answer: The net torque is the vector sum of all individual torques. Individual torques add vectorially.

Flashcard 17: 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 18: Which direction does positive torque rotate an object?

Answer: Counterclockwise. Standard convention for positive rotation.

Flashcard 19: What is the effect of increasing the distance $r$ in the torque formula?

Answer: Increases torque, if force and angle remain constant. Torque is proportional to radius.

Flashcard 20: State the condition for equilibrium of a rotational system.

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

Flashcard 21: Which quantity remains constant for an object in rotational equilibrium?

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

Flashcard 22: 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 23: What is the rotational analog of force in linear motion?

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

Flashcard 24: State the formula for moment of inertia of a point mass.

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

Flashcard 25: 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 26: Identify the unit of torque in SI units.

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

Flashcard 27: State the formula for moment of inertia of a point mass.

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

Flashcard 28: If moment of inertia increases, what happens to angular acceleration?

Answer: Angular acceleration decreases. From $\tau = I\alpha$, larger $I$ means smaller $\alpha$.

Flashcard 29: What is the effect of increasing the distance $r$ in the torque formula?

Answer: Increases torque, if force and angle remain constant. Torque is proportional to radius.

Flashcard 30: What is the role of the pivot point in torque calculations?

Answer: Acts as the reference point for distance and direction. Axis about which rotation and distances measured.

Flashcard 31: In rotational motion, what does $\theta$ represent?

Answer: Angular displacement. Angle rotated from reference position.

Flashcard 32: 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 33: What is the role of the pivot point in torque calculations?

Answer: Acts as the reference point for distance and direction. Axis about which rotation and distances measured.

Flashcard 34: Identify the factor that torque depends on besides force.

Answer: Distance from pivot point and angle of force. Radius and angle determine lever arm effectiveness.

Flashcard 35: 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 36: What is the unit of angular displacement?

Answer: Radians (rad). Standard unit for angle measurement.

Flashcard 37: What happens to torque if the angle $\theta = 0^\text{o}$?

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

Flashcard 38: 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 39: 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 40: What is the condition for equilibrium of a seesaw?

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

Flashcard 41: What is the unit of angular displacement?

Answer: Radians (rad). Standard unit for angle measurement.

Flashcard 42: 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 43: Identify the variable representing angular displacement.

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

Flashcard 44: Identify the factor that torque depends on besides force.

Answer: Distance from pivot point and angle of force. Radius and angle determine lever arm effectiveness.

Flashcard 45: Identify the variable representing angular displacement.

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

Flashcard 46: State the condition for equilibrium of a rotational system.

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

Flashcard 47: What is the condition for equilibrium of a seesaw?

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

Flashcard 48: 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 49: 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 50: What happens to torque if the angle $\theta = 0^\text{o}$?

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

Flashcard 51: 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 52: What is torque's formula?

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

Flashcard 53: What is the condition for rotational equilibrium?

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

Flashcard 54: 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 55: Which direction does negative torque rotate an object?

Answer: Clockwise. Standard convention for negative rotation.

Flashcard 56: What is the rotational analog of mass?

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

Flashcard 57: 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 58: Find the torque if $r = 3 \text{m}$, $F = 4 \text{N}$, $\theta = 90^\text{o}$.

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