NSSCAS Physics (8225) flashcards
NSSCAS Physics (8225) · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Displacement
- Vector quantity representing the straight-line distance and direction from an initial to a final position; its magnitude is not necessarily the total distance travelled.
- Acceleration
- Rate of change of velocity with respect to time; a vector quantity measured in metres per second squared (m s⁻²).
- Projectile motion
- Motion of an object thrown into the air, subject only to gravity and air resistance; horizontal velocity constant, vertical acceleration equal to g downward.
- Centripetal force
- Resultant force directed toward the centre of a circular path that keeps a body moving in that circle; magnitude F = mv²/r.
- Newton's second law
- The resultant force acting on a body is directly proportional to its rate of change of momentum and acts in the direction of that change; F = ma for constant mass.
- Momentum
- Product of a body's mass and velocity; a vector quantity measured in kilogram metres per second (kg m s⁻¹).
- Impulse
- Product of a force and the time for which it acts; equal to the change in momentum of the body on which it acts.
- Principle of moments
- For a body in equilibrium, the sum of clockwise moments about any point equals the sum of anticlockwise moments about the same point.
- Work done
- Energy transferred when a force moves an object through a distance; calculated as force × distance moved in the direction of the force (W = Fs cosθ).
- Kinetic energy
- Energy possessed by a body due to its motion; calculated as ½ × mass × velocity² (KE = ½mv²).
- Power
- Rate of transferring energy or doing work; measured in watts (W), where 1 W = 1 J s⁻¹.
- Efficiency
- Ratio of useful energy output to total energy input, often expressed as a percentage; a measure of how well a device transfers energy.
- Hooke's law
- The extension of a spring or wire is directly proportional to the applied force, provided the limit of proportionality is not exceeded; F = kx.
- Young modulus
- Ratio of tensile stress to tensile strain for a material in the linear region of its stress–strain graph; a measure of stiffness.
- Stress
- Force applied per unit cross-sectional area of a material; measured in pascals (Pa), where 1 Pa = 1 N m⁻².
- Strain
- Ratio of the extension of a material to its original length; a dimensionless quantity, often expressed as a percentage.
- Frequency
- Number of complete oscillations or waves passing a point per second; measured in hertz (Hz).
- Wavelength
- Distance between two consecutive points in phase on a wave, such as crest to crest or trough to trough; measured in metres.
- Refractive index
- Ratio of the speed of light in a vacuum to the speed of light in a medium; also equal to sin i / sin r for light entering from air.
- Critical angle
- Angle of incidence in a denser medium for which the angle of refraction is 90°; total internal reflection occurs for angles greater than this.
- Ohm's law
- Current through a conductor is directly proportional to the potential difference across it, provided physical conditions such as temperature remain constant.
- Resistivity
- Property of a material that quantifies how strongly it opposes the flow of electric current; defined by R = ρL/A.
- Electromotive force
- Energy transferred from other forms to electrical energy per unit charge passing through a source; measured in volts.
- Internal resistance
- Resistance within a source of e.m.f. that causes the terminal potential difference to be less than the e.m.f. when current flows.
- Gravitational field strength
- Gravitational force per unit mass experienced by a small test mass at a point in a gravitational field; measured in N kg⁻¹.
- Electric field strength
- Electric force per unit positive charge experienced by a small test charge at a point in an electric field; measured in N C⁻¹ or V m⁻¹.
- Magnetic flux density
- Measure of the strength of a magnetic field, defined as the force per unit current per unit length on a conductor perpendicular to the field; measured in teslas (T).
- Faraday's law
- The magnitude of an induced e.m.f. is directly proportional to the rate of change of magnetic flux linkage through a circuit.
- Specific heat capacity
- Energy required to raise the temperature of 1 kg of a substance by 1 K (or 1 °C); measured in J kg⁻¹ K⁻¹.
- Specific latent heat
- Energy required to change the state of 1 kg of a substance without a change in temperature; measured in J kg⁻¹.
- Ideal gas equation
- Equation of state for an ideal gas: pV = nRT, where p is pressure, V volume, n amount in moles, R molar gas constant and T absolute temperature.
- Random error
- Unpredictable variation in measurements caused by uncontrolled variables; reduces precision and can be minimised by taking repeated readings and calculating a mean.