Physics terms compared
Two ideas that sound interchangeable and are not. Each page states the distinction first, then shows where it changes an answer, because that is the part an exam actually tests.
Accuracy vs Precision in AP PhysicsAccuracy is closeness to the accepted value, precision is closeness of repeats to each other. What the AP Physics CED actually says, and what it asks instead.Ammeter vs Voltmeter: What Is the Difference?An ammeter goes in series and reads current in amps. A voltmeter goes in parallel and reads potential difference in volts. Why swapping them breaks the circuit.Average vs Instantaneous VelocityAverage velocity is displacement over an interval, the slope of a secant. Instantaneous velocity is the slope of the tangent at one moment. Worked cases.Celsius vs Kelvin: What Is the Difference?Celsius and kelvin have the same size degree and different zeros. That is why a temperature difference is identical in both and an absolute temperature is not.Centripetal vs Centrifugal Force: Which Is Real?Centripetal names an inward direction that real forces point. Centrifugal names no force at all, because no second object exerts an outward push.Concave vs Convex Mirror: What Is the Difference?A concave mirror converges light and can make a real image. A convex mirror diverges it and only ever makes a virtual, upright, reduced one. Signs and examples.Conductor vs Insulator: What Is the Difference?A conductor lets charge carriers move easily; an insulator does not. That one difference sets grounding, induced charge, and the field inside each material.Conservative vs Nonconservative ForceA conservative force does path-independent work, so it has a potential energy. A nonconservative force does path-dependent work and has none.Constructive vs Destructive InterferenceConstructive interference is overlapping waves displacing the medium the same way, destructive is opposite ways. The path difference decides which you get.Distance vs Displacement: The DifferenceDistance is how far you travelled along the path. Displacement is the change in position, start to finish. Table, worked cases, and the marks it costs.Elastic vs Inelastic Collision: How to TellAn elastic collision keeps the system's total kinetic energy; an inelastic one loses some. One test separates them. Table, worked classifications, AP traps.Electric Potential vs Electric Potential EnergyElectric potential is volts at a point in space. Electric potential energy is joules for a charge placed there. U = qV is the bridge, with worked examples.Fission vs Fusion: What Is the Difference?Fission splits one nucleus into smaller ones. Fusion combines smaller nuclei into a larger one. Both conserve nucleon number and release energy via E = mc squared.Heat vs Temperature: What Is the Difference?Heat is energy on the move between systems. Temperature is a property a system has. An object can have a temperature; it cannot have an amount of heat.Heat vs Work: The Difference in ThermodynamicsHeat and work are both energy in transit, and both are positive going into the system on the AP sheet. They differ only in the mechanism of the transfer.Impulse vs Momentum: What Is the Difference?Momentum is the motion a system has right now, mv. Impulse is what a net force delivers over a time interval, and it equals the change in momentum.Isothermal vs Adiabatic: The DifferenceIsothermal holds the temperature fixed, so the change in internal energy is zero. Adiabatic transfers no energy by heating, so Q is zero. One law, two terms.Kinetic vs Potential Energy: The DifferenceKinetic energy belongs to a moving object. Potential energy belongs to a system of two or more objects interacting through a conservative force.Linear vs Angular Velocity: The DifferenceAngular velocity is one number for a whole rigid system. Linear velocity differs for every point on it. v equals r omega, and only in radians.Mass vs Rotational Inertia: The DifferenceMass is one number per object. Rotational inertia is one number per axis, so the same object has many values, and the parallel axis theorem tells you why.Mass vs Weight: What Is the Difference?Mass is how much matter an object has, in kilograms. Weight is the gravitational force on it, in newtons. Move the object and only the weight changes.Period vs Frequency: What Is the Difference?Period is the seconds one cycle takes; frequency is the cycles per second. They are reciprocals, and the beat and averaging cases show why that matters.Real vs Virtual Image: What Is the Difference?A real image forms where light rays actually cross, so a screen catches it. A virtual image forms where rays only appear to come from. Sign rules and examples.Reflection vs Refraction: What Is the Difference?Reflection sends light back into the medium it came from at an equal angle. Refraction sends it into the new medium at a bent angle because its speed changes.Resistance vs Resistivity: What Is the Difference?Resistance belongs to an object and is measured in ohms. Resistivity belongs to the material and is measured in ohm metres. R = rho L / A links them, with examples.Scalar vs Vector: What Is the Difference?A scalar needs only a magnitude, a vector needs a magnitude and a direction. The real difference is how they add. Full AP Physics 1 classification.Speed vs Velocity: What Is the Difference?Speed is how fast, velocity is how fast and which way. Same unit, different quantities: a table, a path that doubles back, and the marks it costs.Standing vs Traveling Waves: The DifferenceA traveling wave carries its pattern forward. A standing wave is two of them interfering inside a confined region, which is why only certain wavelengths fit.Transverse vs Longitudinal Waves: The DifferenceA transverse wave oscillates across its direction of travel and a longitudinal wave along it. The consequence that gets tested: only transverse waves polarize.Voltage vs Current: What Is the Difference?Voltage is energy per charge, in volts. Current is charge per second, in amps. One is measured across an element and one through it. Worked circuit examples.Weight vs Normal Force: What Is the Difference?Weight is gravity pulling the object down at mg. The normal force is a surface pushing perpendicular to itself. They match only on level ground at rest.Work vs Power: What Is the Difference?Work is an amount of energy transferred, in joules. Power is the rate that energy moves, in watts. Same job, any power: table, worked cases, AP traps.