AP Physics 1 Flashcards: Torque And Work

What this deck covers

This deck focuses on Torque And Work, 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: Calculate work: $F = 10 \text{ N}$, $d = 4 \text{ m}$, $\theta = 0°$.

Answer: $W = 40 \text{ J}$. $W = 10 \times 4 \times \cos(0°) = 40$ J.

Flashcard 2: Identify the unit of measure for power in the SI system.

Answer: Watt (W). Power is energy per unit time, so watts = joules/second.

Flashcard 3: What is the effect of torque on angular velocity?

Answer: Changes angular velocity. Torque causes angular acceleration, which changes angular velocity over time.

Flashcard 4: Define the term 'moment arm' in physics.

Answer: Another term for lever arm. Moment arm and lever arm are synonymous terms in rotational mechanics.

Flashcard 5: State the principle of conservation of mechanical energy.

Answer: Total mechanical energy remains constant if only conservative forces act. Energy converts between kinetic and potential but total stays constant.

Flashcard 6: What is the angular displacement in work done by torque?

Answer: The angle through which the object rotates. Angular displacement $\theta$ must be measured in radians for the work formula.

Flashcard 7: Define the term 'moment arm' in physics.

Answer: Another term for lever arm. Moment arm and lever arm are synonymous terms in rotational mechanics.

Flashcard 8: Find the torque if a force of 10 N is applied 2 m from pivot at 90°.

Answer: $\tau = 20 \text{ N·m}$. $\tau = 10 \times 2 \times \sin(90°) = 20$ N·m.

Flashcard 9: State the SI unit for work.

Answer: Joule (J). Work is energy transfer, measured in joules (force × distance).

Flashcard 10: If $\theta = 0°$, what is $\cos(\theta)$ in the work formula?

Answer: $\cos(\theta) = 1$. When force and displacement are parallel, maximum work is done.

Flashcard 11: State the SI unit for work.

Answer: Joule (J). Work is energy transfer, measured in joules (force × distance).

Flashcard 12: What is the formula for gravitational potential energy?

Answer: $U = mgh$. Potential energy depends on mass, gravity, and height above reference.

Flashcard 13: What is the formula for work done by a constant force?

Answer: $W = F \cdot d \cdot \cos(\theta)$. Where $F$ is force, $d$ is displacement, and $\theta$ is angle between them.

Flashcard 14: How is net work related to net force?

Answer: Net work is done by net force. Net work is the sum of work done by all forces acting.

Flashcard 15: What is the effect of a force with no lever arm on torque?

Answer: Produces zero torque. Zero lever arm means the force passes through the rotation axis.

Flashcard 16: Identify the condition for equilibrium in terms of net torque.

Answer: Net torque must be zero. No net rotation occurs when clockwise and counterclockwise torques balance.

Flashcard 17: What is the formula for torque ($\tau$) in terms of force and lever arm?

Answer: $\tau = r \cdot F \cdot \sin(\theta)$. Where $r$ is lever arm, $F$ is force magnitude, and $\theta$ is angle between force and lever arm.

Flashcard 18: Calculate power: $W = 200 \text{ J}$, $t = 5 \text{ s}$.

Answer: $P = 40 \text{ W}$. $P = \frac{200}{5} = 40$ W.

Flashcard 19: Which angle maximizes torque for a given force and lever arm?

Answer: 90 degrees or $\frac{\pi}{2}$ radians. Maximum torque occurs when force is perpendicular to lever arm ($\sin(90°) = 1$).

Flashcard 20: State the formula for power in terms of work and time.

Answer: $P = \frac{W}{t}$. Power equals work divided by the time taken to do that work.

Flashcard 21: What is the rotational equivalent of mass in linear motion?

Answer: Moment of inertia. Moment of inertia measures resistance to angular acceleration.

Flashcard 22: Calculate the torque: $F = 15 \text{ N}$, $r = 3 \text{ m}$, $\theta = 30°$.

Answer: $\tau = 22.5 \text{ N·m}$. $\tau = 15 \times 3 \times \sin(30°) = 45 \times 0.5 = 22.5$ N·m.

Flashcard 23: What is the rotational equivalent of mass in linear motion?

Answer: Moment of inertia. Moment of inertia measures resistance to angular acceleration.

Flashcard 24: Identify the condition for equilibrium in terms of net torque.

Answer: Net torque must be zero. No net rotation occurs when clockwise and counterclockwise torques balance.

Flashcard 25: Define lever arm in the context of torque.

Answer: Perpendicular distance from axis of rotation to line of action of force. The shortest distance determines the effectiveness of the applied force.

Flashcard 26: Calculate the work done by a 5 N force over 3 m in the same direction.

Answer: $W = 15 \text{ J}$. $W = 5 \times 3 \times \cos(0°) = 15$ J.

Flashcard 27: What is the formula for instantaneous power in terms of force and velocity?

Answer: $P = F \cdot v \cdot \cos(\theta)$. Where $v$ is velocity and $\theta$ is angle between force and velocity vectors.

Flashcard 28: What is the work done by a force perpendicular to displacement?

Answer: Zero. Perpendicular force means $\theta = 90°$, so $\cos(90°) = 0$.

Flashcard 29: What is the formula for rotational work?

Answer: $W = \tau \cdot \theta$. Where $\tau$ is torque and $\theta$ is angular displacement in radians.

Flashcard 30: If power is 50 W and time is 2 s, what is the work done?

Answer: $W = 100 \text{ J}$. $W = P \times t = 50 \times 2 = 100$ J.

Flashcard 31: What is the formula for gravitational potential energy?

Answer: $U = mgh$. Potential energy depends on mass, gravity, and height above reference.

Flashcard 32: What is the effect of zero net torque on an object's rotation?

Answer: No change in rotational motion. Zero net torque means constant angular velocity (including zero).

Flashcard 33: State the formula for power in terms of work and time.

Answer: $P = \frac{W}{t}$. Power equals work divided by the time taken to do that work.

Flashcard 34: How is net work related to net force?

Answer: Net work is done by net force. Net work is the sum of work done by all forces acting.

Flashcard 35: State the unit of torque in the International System of Units (SI).

Answer: Newton meter (N·m). Torque combines force and distance, so units are force × distance.

Flashcard 36: What happens to torque if the lever arm is doubled?

Answer: Torque is doubled. Torque is directly proportional to lever arm in the formula.

Flashcard 37: Calculate the work done by a 5 N force over 3 m in the same direction.

Answer: $W = 15 \text{ J}$. $W = 5 \times 3 \times \cos(0°) = 15$ J.

Flashcard 38: What is the relationship between force and torque?

Answer: Torque is the rotational equivalent of force. Torque causes rotation just as force causes linear acceleration.

Flashcard 39: What is the condition for mechanical equilibrium?

Answer: Net force and net torque must both be zero. Object neither translates nor rotates when all forces and torques balance.

Flashcard 40: Find the torque if a force of 10 N is applied 2 m from pivot at 90°.

Answer: $\tau = 20 \text{ N·m}$. $\tau = 10 \times 2 \times \sin(90°) = 20$ N·m.

Flashcard 41: What is the effect of zero net torque on an object's rotation?

Answer: No change in rotational motion. Zero net torque means constant angular velocity (including zero).

Flashcard 42: What is the angular displacement in work done by torque?

Answer: The angle through which the object rotates. Angular displacement $\theta$ must be measured in radians for the work formula.

Flashcard 43: If $\theta = 0°$, what is $\cos(\theta)$ in the work formula?

Answer: $\cos(\theta) = 1$. When force and displacement are parallel, maximum work is done.

Flashcard 44: How does torque affect rotational motion?

Answer: Causes angular acceleration. Net torque produces angular acceleration according to $\tau = I\alpha$.

Flashcard 45: How does torque affect rotational motion?

Answer: Causes angular acceleration. Net torque produces angular acceleration according to $\tau = I\alpha$.

Flashcard 46: What is the formula for instantaneous power in terms of force and velocity?

Answer: $P = F \cdot v \cdot \cos(\theta)$. Where $v$ is velocity and $\theta$ is angle between force and velocity vectors.

Flashcard 47: State the work-energy principle.

Answer: Work done on an object equals change in kinetic energy. Net work equals the change in kinetic energy of the object.

Flashcard 48: Calculate work: $F = 10 \text{ N}$, $d = 4 \text{ m}$, $\theta = 0°$.

Answer: $W = 40 \text{ J}$. $W = 10 \times 4 \times \cos(0°) = 40$ J.

Flashcard 49: Identify the rotational analog of Newton's second law.

Answer: $\tau = I\alpha$. Relates torque to moment of inertia and angular acceleration.

Flashcard 50: What is the effect of torque on angular velocity?

Answer: Changes angular velocity. Torque causes angular acceleration, which changes angular velocity over time.

Flashcard 51: State the unit of torque in the International System of Units (SI).

Answer: Newton meter (N·m). Torque combines force and distance, so units are force × distance.

Flashcard 52: Define lever arm in the context of torque.

Answer: Perpendicular distance from axis of rotation to line of action of force. The shortest distance determines the effectiveness of the applied force.

Flashcard 53: State the principle of conservation of mechanical energy.

Answer: Total mechanical energy remains constant if only conservative forces act. Energy converts between kinetic and potential but total stays constant.

Flashcard 54: Which angle maximizes torque for a given force and lever arm?

Answer: 90 degrees or $\frac{\pi}{2}$ radians. Maximum torque occurs when force is perpendicular to lever arm ($\sin(90°) = 1$).

Flashcard 55: What is the formula for kinetic energy?

Answer: $KE = \frac{1}{2}mv^2$. Kinetic energy depends on mass and the square of velocity.

Flashcard 56: What happens to torque if the lever arm is doubled?

Answer: Torque is doubled. Torque is directly proportional to lever arm in the formula.

Flashcard 57: What is the condition for mechanical equilibrium?

Answer: Net force and net torque must both be zero. Object neither translates nor rotates when all forces and torques balance.

Flashcard 58: What is the relationship between work and energy?

Answer: Work is the transfer of energy. Work changes an object's kinetic or potential energy state.

Flashcard 59: If power is 50 W and time is 2 s, what is the work done?

Answer: $W = 100 \text{ J}$. $W = P \times t = 50 \times 2 = 100$ J.

Flashcard 60: What is the relationship between force and torque?

Answer: Torque is the rotational equivalent of force. Torque causes rotation just as force causes linear acceleration.

Flashcard 61: Calculate gravitational work: $m = 2 \text{ kg}$, $g = 9.8 \text{ m/s}^2$, $h = 5 \text{ m}$.

Answer: $W = 98 \text{ J}$. $W = mgh = 2 \times 9.8 \times 5 = 98$ J.

Flashcard 62: What is the formula for work done by a constant force?

Answer: $W = F \cdot d \cdot \cos(\theta)$. Where $F$ is force, $d$ is displacement, and $\theta$ is angle between them.

Flashcard 63: Calculate power: $W = 200 \text{ J}$, $t = 5 \text{ s}$.

Answer: $P = 40 \text{ W}$. $P = \frac{200}{5} = 40$ W.

Flashcard 64: What is the formula for rotational work?

Answer: $W = \tau \cdot \theta$. Where $\tau$ is torque and $\theta$ is angular displacement in radians.

Flashcard 65: What is the formula for torque ($\tau$) in terms of force and lever arm?

Answer: $\tau = r \cdot F \cdot \sin(\theta)$. Where $r$ is lever arm, $F$ is force magnitude, and $\theta$ is angle between force and lever arm.

Flashcard 66: Calculate gravitational work: $m = 2 \text{ kg}$, $g = 9.8 \text{ m/s}^2$, $h = 5 \text{ m}$.

Answer: $W = 98 \text{ J}$. $W = mgh = 2 \times 9.8 \times 5 = 98$ J.

Flashcard 67: Identify the rotational analog of Newton's second law.

Answer: $\tau = I\alpha$. Relates torque to moment of inertia and angular acceleration.

Flashcard 68: What is the work done by a force perpendicular to displacement?

Answer: Zero. Perpendicular force means $\theta = 90°$, so $\cos(90°) = 0$.

Flashcard 69: What is the effect of a force with no lever arm on torque?

Answer: Produces zero torque. Zero lever arm means the force passes through the rotation axis.

Flashcard 70: What is the relationship between work and energy?

Answer: Work is the transfer of energy. Work changes an object's kinetic or potential energy state.

Flashcard 71: Identify the unit of measure for power in the SI system.

Answer: Watt (W). Power is energy per unit time, so watts = joules/second.

Flashcard 72: Calculate the torque: $F = 15 \text{ N}$, $r = 3 \text{ m}$, $\theta = 30°$.

Answer: $\tau = 22.5 \text{ N·m}$. $\tau = 15 \times 3 \times \sin(30°) = 45 \times 0.5 = 22.5$ N·m.