Second year Physics

• Independent Variable


  A variable that is intentionally changed or manipulated during an experiment, while keeping all other variables constant.
• Dependent Variable


  A variable that is measured or observed in response to a change made to the independent variable, during an experiment.
• Fair Test


  A test where only one variable is changed at a time, while keeping all other variables constant, to ensure that the outcome is solely due to the changed variable.
• Control Variables


  Variables that are kept constant during an experiment to eliminate their effect and ensure that the outcome is due to the changed independent variable.
• Line Graph


  A graph with a horizontal x-axis and a vertical y-axis, used to show the relationship between two variables. Each axis should have a label with units and the axes should align correctly.
• Line of Best Fit

  A single line that best represents the general relationship between two variables, without connecting the individual data points, in a line graph.
• Describe Trend


  To identify and summarize the overall pattern or direction of change in graphical data, including the direction of change, steepness, and any notable features or anomalies.
• Anomalous Data Point


  A data point that does not follow the general pattern or trend of the other data points, requiring further investigation.
• Direct Proportion


  A relationship where if one variable doubles, the other variable also doubles, with all points on the line of best fit passing through the origin.
• Straight Line Graph


  A graph that indicates direct proportion, with a line of best fit that passes through the origin, showing that each variable is directly proportional to the other.
• Repeat Readings


  Taking multiple measurements of a variable to improve the reliability and accuracy of experimental results by reducing the effect of random errors.
• m to km


  1 km = 1000 m
• Convert between days, hours, and minutes to seconds:

  1 second = 1/86,400 hours 1 hour = 3600 seconds 1 day = 24 hours = 86,400 seconds
• Standard Form


  A way of writing large or small numbers in a simplified form using powers of 10, for example: 1.23 x 10^5 or 4.56 x 10^-3.
• Unit Prefixes


  A series of prefixes used to represent powers of 10 in scientific notation, including: + k (kilo, 10^3) + G (giga, 10^9) + M (mega, 10^6) + m (milli, 10^-3) + μ (micro, 10^-6) + n (nano, 10^-9)
• Resultant Force


  The combined force acting on an object, resulting from the sum of multiple forces, which can be calculated using vector addition.
• Newtons First Law


  An object at rest will remain at rest, and an object in motion will continue to move with a constant velocity, unless acted upon by an external force.
• Newton's Law Application


  Using Newton's first law to determine whether an object is moving at a constant speed or accelerating, and to analyze the motion of objects in various situations.
• Newtons Third Law


  For every action there is an equal and opposite reaction, meaning that forces always come in pairs.
• Newton's Law Application


  Using Newton's third law to analyze and understand the interactions between objects, such as a rocket's motion or the motion of a swimmer or ice skater, and their reaction forces.
• Speed Equation


  The formula for calculating speed, Speed (v) = Distance (d) ÷ Time (t), or v = d/t.
• Average vs Instantaneous Speed

  Understanding the difference between: + Average speed: total distance travelled ÷ total time taken + Instantaneous speed: the speed at a specific moment in time
• Terminal Velocity


  The maximum speed an object can reach as it falls under gravity, at which point the force of gravity is balanced by the force of air resistance, also known as the terminal velocity.
• Newton's 1st Law (Terminal Velocity)


  At terminal velocity, Newton's first law applies, stating that the object will continue to move at constant speed (no net force acting on it), without accelerating upwards or downwards.
• Planet Types


  Differentiating between rocky planets (Mercury, Venus, Earth, Mars) and gaseous planets (Jupiter, Saturn, Uranus, Neptune) based on their composition.
• Astronomy Terms


  + Star: a massive ball of hot, glowing gas + Planet: a natural satellite that orbits around stars + Moon: a natural satellite that orbits around planets or stars + Comet: a small, icy body that releases gas and dust as it approaches the Sun + Solar System: the group of celestial objects that orbit around the Sun + Galaxy: a large grouping of stars, gas, and dust bound together by gravity + Universe: the totality of all existence, containing all matter and energy
• Day and Year


  + Day: the period of time it takes the Earth to rotate once on its axis, about 24 hours. + Year: the time it takes the Earth to orbit the Sun once, about 365.25 days.
• Day and Night


  The rotation of the Earth on its axis causes day and night, with the Sun appearing above the horizon during the day and below it at night, resulting in alternating cycles of light and darkness.
• Trend of Year Length

  The length of a year for a planet inversely correlates with its average distance from the Sun, meaning that planets with longer years tend to be farther away from the Sun.
• Longest Day


  The planet that has a day longer than a year is Venus, with a sidereal day (the time it takes the planet to rotate once on its axis) of 243 Earth days.
• Astronomical Unit


  A unit of length used in astronomy, equivalent to the average distance between the Earth and the Sun, approximately 149.6 million kilometers (92.96 million miles).
• Light Year


  A unit of distance used in astronomy, equivalent to the distance light travels in one year, approximately 9.461 billion kilometers (5.88 billion miles).
• Factors Affecting Weight


  + Force of gravity (gravitational field strength) + Mass of the object + Distance from the center of mass
• Weight Equation


  The formula for calculating weight, Weight (gravitational force) = mass x gravitational field strength, or W = mg, where W is the weight, m is the mass, and g is the gravitational field strength.
• Orbital Speed Equation


  The formula for calculating orbital speed, Orbital speed = 2 × π × radius / orbital period, or v = 2πr/ T, where v is the orbital speed, r is the radius, and T is the orbital period.
• Electricity


  The transfer of energy through the flow of electrons, allowing for the efficient transmission of power.
• Working Circuit


  A circuit requires: + An energy source (power supply) + A complete circuit (connected components) + A device to transfer electrical energy (load)
• Current


  Additive unit of electric current, measured in amperes (A), measures the rate of flow of electrons and is measured using an ammeter connected in series.
• Voltage


  Energetic unit of electric potential, measured in volts (V), measures energy transfer per electron and is measured using a voltmeter connected in parallel.
• Units of Current and Voltage


  + Current (I): measured in amperes (A) + Voltage (V): measured in volts (V)