Checklist for Revision: Read each sentence from the syllabus, understand it, and mark it as confident, unsure, or not okay.
Measuring Length: Use rulers, measuring cylinders, and other instruments. Know how to determine average values for small distances and time intervals.
SI Units:
Length: meters (m)
Time: seconds (s)
Mass: kilograms (kg)
Temperature: Kelvin (K)
Electric Current: ampere (A)
Prefixes: Kilo (×1000), Centi (÷100), Milli (÷1000). Ability to convert between units.
Measuring Length and Volume
Length: Ruler for up to a meter, measuring tape for long distances, micrometer for thin objects.
Volume for Regular Solids: Use geometric equations.
Volume for Irregular Solids: Displacement method (use measuring cylinder, record initial and final volume).
Measuring Time
Time Intervals: Use stopwatches, clocks, and timers. Convert between hours, minutes, and seconds.
Pendulum: Measure the time of multiple oscillations and divide by the number of cycles to get the time for one oscillation.
Mass and Weight
Mass: Amount of matter in an object. Use a balance to measure.
Weight: Gravitational force on an object. Calculated as W = mg (mass × gravitational field strength).
Earth's Gravitational Field Strength: 9.8 N/kg, equivalent to the acceleration of free fall.
Measuring Mass of Liquids: Use an empty container, measure it, fill the liquid, and subtract the container's mass.
Density
Definition: Mass per unit volume (ρ = m/V).
Units: kg/m³ or g/cm³.
Measuring Density:
Regular solids: Measure mass and volume part by part.
Liquids: Using a measuring cylinder.
Irregular solids: Displacement method.
Floating and Sinking: Compare densities; if less dense than the liquid, it floats, and if denser, it sinks.
Effect of Temperature: Increasing temperature generally decreases density due to thermal expansion.
Scalars and Vectors
Scalars: Only magnitude (e.g., distance, speed, time, mass, energy).
Vectors: Magnitude and direction (e.g., force, weight, velocity, acceleration).
Resultant Vectors: Calculated using the Pythagoras theorem for right-angled vectors: [ R = \sqrt{(A^2 + B^2)} ].
Direction: Use trigonometric functions to find the angle (e.g., tan θ = opposite/adjacent).
Graphical Method: Vector diagrams to scale.
Motion and Speed-Time Graphs
Speed: Distance over time (d/t).
Velocity: Speed with a given direction.
Speed-Time Graphs:
Constant speed (horizontal line)
Acceleration (sloped line)
Deceleration (curved line downwards)
Calculate distance as the area under the graph.
Acceleration: Change in velocity over time, including both positive (acceleration) and negative (deceleration).
Newton’s Laws of Motion
First Law: Objects at rest remain at rest, and objects in motion remain in motion at a constant velocity, unless acted upon by an external force.
Second Law: Force is equal to mass times acceleration (F = ma).
Third Law: For every action, there is an equal and opposite reaction.
Circular Motion and Free Fall
Circular Motion: Force (centripetal force) acts towards the center, depends on speed, mass, and radius of the circle.
Free Fall: In absence of air resistance, objects fall at constant acceleration due to gravity (9.8 m/s²). With air resistance, objects can reach terminal velocity.
Skydivers and Parachutes: Accelerate until air resistance equals weight, after which they fall at terminal velocity.
Forces
Types of Friction: Solid friction (between two surfaces) and drag (air/water resistance).
Solid Friction: Depends on the roughness of surfaces, produces heat.
Drag: Increases with speed and surface area.
Hooke’s Law: Force in a spring is proportional to the extension until the limit of proportionality (F = kx).
Momentum
Definition: Mass times velocity (p = mv).
Impulse: Force times time (Ft), equal to change in momentum (Δp).
Conservation of Momentum: The total momentum before a collision is equal to the total momentum after the collision, in a closed system.
Calculations: Use momentum and impulse equations to solve real-world problems.