MATSEC SEC Physics flashcards
MATSEC SEC Physics · Build recall with a focused review session.
33 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Average speed
- Total distance travelled divided by the total time taken, measured in metres per second. It ignores direction and is not the same as average velocity.
- Acceleration
- The rate of change of velocity, calculated as change in velocity divided by time taken. Unit is metres per second squared; deceleration is negative acceleration.
- Newton's second law
- The resultant force on a body equals its mass multiplied by its acceleration, F = ma. Force in newtons, mass in kilograms, acceleration in metres per second squared.
- Terminal velocity
- The constant maximum speed reached by a falling object when air resistance equals its weight. Resultant force is then zero, so acceleration is zero.
- Moment of a force
- The turning effect of a force, calculated as force multiplied by the perpendicular distance from the pivot. Unit is the newton metre.
- Kinetic energy
- Energy a body possesses because of its motion, given by KE = ½mv². Doubling the speed quadruples the kinetic energy for the same mass.
- Work done
- Energy transferred when a force moves an object through a distance, W = Fd, where F acts along the displacement. Measured in joules.
- Power
- The rate of transferring energy or doing work, P = E/t or W/t. Measured in watts, where one watt equals one joule per second.
- Conservation of energy
- Energy cannot be created or destroyed, only transferred between stores. Total energy before and after any process remains the same.
- Efficiency
- Useful energy output divided by total energy input, expressed as a percentage. Real machines always have efficiency below 100% because energy is dissipated.
- Wave equation
- Wave speed equals frequency multiplied by wavelength, v = fλ. Frequency is in hertz, wavelength in metres, speed in metres per second.
- Refraction
- The change in direction of a wave when it crosses a boundary between media of different speeds. Light bends towards the normal entering a denser medium.
- Law of reflection
- The angle of incidence equals the angle of reflection, both measured from the normal to the reflecting surface. The incident ray, normal and reflected ray lie in one plane.
- Longitudinal wave
- A wave in which particle oscillations are parallel to the direction of energy transfer, such as sound. It consists of compressions and rarefactions.
- Specific heat capacity
- The energy needed to raise the temperature of one kilogram of a substance by one degree Celsius. Energy change is E = mcΔθ.
- Specific latent heat
- The energy needed to change the state of one kilogram of a substance without changing its temperature, E = mL. Melting and boiling both require energy input.
- Conduction
- Transfer of thermal energy through a solid by particle vibrations and free electrons, without bulk movement of the material. Metals conduct well due to free electrons.
- Convection
- Transfer of thermal energy in fluids by the movement of warmer, less dense regions rising and cooler, denser regions sinking. It cannot occur in solids.
- Boyle's law
- For a fixed mass of gas at constant temperature, pressure multiplied by volume is constant, p₁V₁ = p₂V₂. Doubling pressure halves the volume.
- Ohm's law
- For an ohmic conductor at constant temperature, current is directly proportional to potential difference, V = IR. Resistance is measured in ohms.
- Series circuit
- A circuit in which components form a single path, so the current is the same everywhere. Total resistance equals the sum of individual resistances.
- Parallel circuit
- A circuit in which components are connected across the same potential difference. Total current is the sum of branch currents and total resistance is less than any branch.
- Electrical power
- The rate of energy transfer in a circuit, P = VI, also written I²R or V²/R. Measured in watts; energy transferred is power multiplied by time.
- Electromagnetic induction
- The generation of an emf in a conductor when magnetic flux through it changes. Moving a magnet into a coil induces a current.
- Density
- Mass per unit volume of a material, ρ = m/V, measured in kilograms per cubic metre. Objects less dense than a fluid float in it.
- Pressure
- Force acting normally per unit area, p = F/A, measured in pascals. One pascal equals one newton per square metre.
- Pressure in a liquid
- Pressure due to a liquid column equals density × gravitational field strength × depth, p = ρgh. It depends on depth, not on container shape.
- Archimedes' principle
- The upthrust on a body in a fluid equals the weight of fluid it displaces. A body floats when upthrust equals its weight.
- Hooke's law
- The extension of a spring is directly proportional to the force applied, up to the limit of proportionality. Expressed as F = kx with k in N/m.
- Random error
- Variation in readings caused by uncontrolled factors, scattering results about a mean value. Reduced by taking repeated readings and averaging them.
- Systematic error
- A consistent shift of all readings in the same direction, caused by faulty apparatus or poor technique. It is not reduced by repeating readings.
- Precision and accuracy
- Precision is how close repeated readings are to each other; accuracy is how close a reading is to the true value. A precise set may still be inaccurate.
- Gradient of a graph
- The change in the y-axis quantity divided by the change in the x-axis quantity between two points on the line. Its unit is y-unit per x-unit.