AP Physics 1 flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Displacement

The vector change in position from start to finish, independent of path length traveled; it is the quantity used to compute average velocity.

Instantaneous velocity

The velocity at a single moment, equal to the slope of the position-time graph at that point and the limit of Δx/Δt as Δt approaches zero.

Constant-acceleration kinematics

For uniform acceleration, v = v₀ + at, Δx = v₀t + ½at², and v² = v₀² + 2aΔx describe motion along one dimension.

Free-fall acceleration

Near Earth's surface, an object in free fall accelerates downward at about 9.8 m/s² regardless of mass when air resistance is negligible.

Projectile motion

Two-dimensional motion with constant horizontal velocity and constant vertical acceleration g; the components are independent and combine as vectors.

Newton's second law

The net force on an object equals its mass times acceleration, ΣF = ma, with forces added as vectors in a chosen coordinate system.

Newton's third law

For every force one object exerts on another, the second exerts an equal and opposite force on the first; these act on different objects.

Static friction maximum

Static friction adjusts up to a maximum f_s ≤ μ_sN to prevent sliding; once sliding begins, kinetic friction f_k = μ_kN applies.

Incline force components

On a frictionless incline of angle θ, the weight component along the slope is mg sin θ and the normal force is mg cos θ.

Centripetal acceleration

For circular motion, acceleration magnitude is v²/r directed toward the center; it changes direction of velocity, not speed.

Work by a force

W = Fd cos θ, the product of force, displacement, and the cosine of the angle between them; perpendicular forces do zero work.

Work-kinetic energy theorem

The net work done on an object equals its change in kinetic energy, W_net = ½mv² − ½mv₀².

Mechanical energy conservation

When only conservative forces do work, the sum of kinetic and potential energy stays constant throughout the motion.

Power

The rate at which work is done or energy transferred, P = W/Δt; for constant force it also equals Fv cos θ.

Impulse-momentum theorem

Impulse equals change in momentum, J = F_avgΔt = Δp; the area under a force-time graph gives the impulse.

Momentum conservation

If the net external force on a system is zero, total momentum stays constant through collisions and explosions.

Perfectly inelastic collision

A collision in which objects stick together, conserving momentum but losing the maximum kinetic energy consistent with that momentum.

Elastic collision

A collision that conserves both total momentum and total kinetic energy; in one dimension with equal masses, the objects exchange velocities.

Torque

τ = rF sin θ, the rotational effect of a force applied at distance r from a pivot; maximum when force is perpendicular to the position vector.

Moment of inertia

I = Σmr², a measure of resistance to angular acceleration that depends on how mass is distributed about the chosen axis.

Rotational Newton's second law

The net torque about an axis equals the moment of inertia about that axis times angular acceleration, Στ = Iα.

Rolling without slipping

A wheel's contact point is instantaneously at rest, linking linear and angular motion by v = ωR and a = αR.

Parallel-axis theorem

The moment of inertia about any axis is I = I_cm + Md², where d is the distance from the center-of-mass axis.

Rotational kinetic energy

The energy of rotation is K = ½Iω²; a rolling object also has ½mv² of translational kinetic energy.

Angular momentum conservation

When net external torque is zero, total angular momentum L = Iω stays constant, so reducing I increases ω.

Rolling down a ramp

An object released from height h reaches speed v = √(2gh/(1 + I/(MR²))); larger I/(MR²) means slower descent.

Simple harmonic motion

Oscillation driven by a restoring force proportional to displacement, F = −kx, producing sinusoidal motion with constant period.

Mass-spring period

A mass on an ideal spring oscillates with T = 2π√(m/k), independent of amplitude; larger mass or softer spring increases period.

Pendulum period

A simple pendulum has T = 2π√(L/g) for small angles, independent of mass and, approximately, of amplitude.

Resonance

When a periodic driving frequency matches a system's natural frequency, the amplitude of oscillation grows to a maximum.

Buoyant force

The upward force on a submerged or floating object equals the weight of displaced fluid, F_b = ρ_fluid V_displaced g.

Continuity equation

For incompressible flow, A₁v₁ = A₂v₂, so fluid moves faster where a pipe narrows.

Bernoulli's equation

Along a streamline of ideal flow, P + ½ρv² + ρgy is constant, so faster fluid corresponds to lower pressure.