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

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

Flashcard 2: 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 3: 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 4: 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 5: State the SI unit for work.

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

Flashcard 6: 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 7: 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 8: 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 9: 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 10: 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 11: How does torque affect rotational motion?

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

Flashcard 12: What is the formula for rotational work?

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

Flashcard 13: Calculate power: $W = 200 \text{ J}$, $t = 5 \text{ s}$.

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

Flashcard 14: 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 15: 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 16: What is the rotational equivalent of mass in linear motion?

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

Flashcard 17: What is the formula for gravitational potential energy?

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

Flashcard 18: 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 19: 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 20: 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 21: 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 22: 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 23: Identify the rotational analog of Newton's second law.

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

Flashcard 24: 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 25: 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 26: How does torque affect rotational motion?

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

Flashcard 27: 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 28: 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 29: 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 30: 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.