Physics flashcards, generated for you.

Velocity is a vector quantity representing the rate of change of displacement with direction (m/s). Speed is a scalar quantity representing the rate of change of distance without direction. Example: 60 m/s north vs. 60 m/s.

Acceleration is the rate of change of velocity over time: a = Δv/Δt (m/s²). It is a vector and can result from changes in speed, direction, or both. Example: a car increasing speed by 10 m/s every 2 seconds has a = 5 m/s².

F_net = ma. A net force applied to an object produces an acceleration proportional to the force and inversely proportional to the mass. Mechanism: forces cause changes in motion; greater mass requires greater force for the same acceleration.

Kinetic friction acts on moving objects: f_k = μ_k × N. Static friction acts on stationary objects and adjusts up to a maximum: f_s ≤ μ_s × N. Static friction coefficient is typically larger. Both oppose motion/applied force respectively.

Work W = F·d·cos(θ), where F is force, d is displacement, and θ is the angle between them (Joules). Mechanism: work transfers energy to an object. If force is parallel to displacement (θ = 0°), W = Fd. If perpendicular (θ = 90°), W = 0.

The work-energy theorem states: W_net = ΔKE = ½m(v_f² − v_i²). Mechanism: net work done on an object equals its change in kinetic energy. Consequence: an object starting at rest requires W = ½mv² of work to reach velocity v.

A conservative force has work independent of path; mechanical energy is conserved. Gravity: U_g = mgh (near Earth's surface); elastic spring: U_s = ½kx². Non-conservative: friction, air resistance (dissipate energy as heat).

Mechanical energy is conserved when only conservative forces act: E_total = KE + PE = constant. Solution: E_initial = mgh_initial = 2(10)(5) = 100 J. At h=1 m: 100 = ½(2)v² + 2(10)(1) → 100 = v² + 20 → v = √80 ≈ 8.94 m/s.

Momentum p = mv (kg·m/s). Impulse J = FΔt = Δp. Theorem: the impulse applied to an object equals its change in momentum. Mechanism: a force applied over time changes an object's momentum. Example: catching a ball applies a large force over short time to reduce its momentum to zero.

In isolated systems, total momentum is conserved: p_before = p_after. Solution: m₁v₁ + m₂v₂ = (m₁ + m₂)v_f → 3(4) + 2(0) = 5v_f → 12 = 5v_f → v_f = 2.4 m/s. The combined mass moves at 2.4 m/s; kinetic energy is lost (inelastic collision).