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Led by Isaac Newton Simulacrum
Seven tutorials covering AQA GCSE Physics §4.5 Forces — the largest content area in the specification — from forces and gravity through work and elasticity, moments and pressure, describing motion, Newton's Laws, stopping distance, and momentum. Taught by simulacra of the mechanicians who gave us the modern account of how the physical world moves.
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Led by Galileo Galilei Simulacrum
The question
What is a force, and what is the difference between the mass of an object and its weight?
Territory
scalar and vector quantities · vectors represented as arrows (magnitude and direction) · contact forces (friction, air resistance, tension, normal contact) · non-contact forces (gravity, electrostatic, magnetic) · weight W = mg · mass vs weight · gravitational field strength g · centre of mass · weight measured with calibrated spring-balance (newton-meter) · weight proportional to mass · resultant forces · calculating the resultant of two forces in a straight line · (HT) free body diagrams · (HT) balanced forces and equilibrium · (HT) resolving a force into two perpendicular components · (HT) vector diagrams for resolution, equilibrium, and resultant determination
Outcome
The student can distinguish scalars from vectors, give examples of contact and non-contact forces, apply W = mg, distinguish mass from weight, calculate the resultant of two forces in a straight line, and (Higher Tier) draw free body diagrams and resolve forces into perpendicular components. (AQA 4.5.1.1, 4.5.1.2, 4.5.1.3, 4.5.1.4)
Led by Robert Hooke Simulacrum
The question
When a force moves an object, what happens to the energy — and when a force stretches a spring, what is stored inside?
Territory
W = Fs · 1 joule = 1 newton-metre · energy transfer when work is done · work done against friction raises temperature · forces that change the shape of an object (stretching, bending, compressing) require at least two forces applied to a stationary object · elastic versus inelastic deformation · F = ke for springs and compressible elastic objects (within the limit of proportionality) · linear versus non-linear force-extension relationships · calculating spring constant k from linear data · Ee = ½ke² (given on the equation sheet — cross-reference to Course 1 Module 2) · energy stored and energy transfer in a stretched spring · required practical 6 (investigate the relationship between force and extension for a spring)
Outcome
The student can apply W = Fs and reason about the energy transfer in mechanical work, distinguish elastic from inelastic deformation, apply F = ke within the limit of proportionality, calculate a spring constant from data, apply Ee = ½ke² for the energy stored in a stretched or compressed spring, and carry out Required Practical 6. (AQA 4.5.2, 4.5.3)
Led by Archimedes Simulacrum
The question
How does a lever let you lift a weight many times your own, and why does a submarine need to be built thicker the deeper it dives?
Territory
forces and rotation · the moment M = Fd · balance condition (clockwise moments = anticlockwise moments) · calculating force or distance for a balanced object · simple levers · simple gear systems · fluids (liquids and gases) exert pressure normal to any surface · p = F/A · (Higher Tier) p = hρg for a column of liquid · (Higher Tier) why pressure in a liquid increases with depth and density · (Higher Tier) upthrust and its origin in pressure difference between upper and lower surfaces · (Higher Tier) factors influencing floating and sinking · a simple model of the Earth's atmosphere · why atmospheric pressure decreases with altitude
Outcome
The student can apply M = Fd, use the balance condition to find an unknown force or distance, explain how simple levers and gears transmit rotational effects, apply p = F/A, (Higher Tier) apply p = hρg and reason about upthrust and floating, and describe atmospheric pressure and its altitude dependence. (AQA 4.5.4, 4.5.5.1, 4.5.5.2)
Led by Christiaan Huygens Simulacrum
The question
How do you describe the motion of an object precisely enough that another person, given your description, could predict where it will be at any later time?
Territory
distance (scalar) and displacement (vector) · speed (scalar) and velocity (vector) · typical speeds for walking (~1.5 m/s), running (~3 m/s), cycling (~6 m/s) · typical speed of sound in air (~330 m/s) · s = vt for uniform motion · average speed for non-uniform motion · distance-time graphs and the gradient as speed · (HT) drawing tangents to curved distance-time graphs · (HT) motion in a circle — constant speed, changing velocity · acceleration a = Δv/t · deceleration · velocity-time graphs and the gradient as acceleration · (HT) distance travelled as area under velocity-time graph · v² − u² = 2as (given on equation sheet) · free fall acceleration ~9.8 m/s² · terminal velocity in a fluid
Outcome
The student can distinguish scalar from vector motion quantities, apply s = vt and a = Δv/t, draw and interpret distance-time and velocity-time graphs, apply v² − u² = 2as, recall typical speeds, and (Higher Tier) find distance from the area under a velocity-time graph and explain circular motion. (AQA 4.5.6.1)
Led by Isaac Newton Simulacrum
The question
What are the three laws that explain every mechanical motion in the ordinary world?
Territory
Newton's First Law (zero resultant force → stationary stays stationary, moving stays at constant velocity) · resistive forces balancing driving forces in steady motion · velocity only changes when there is a resultant force · (HT) inertia as the tendency to continue in rest or uniform motion · Newton's Second Law: F = ma · direct and inverse proportionality · (HT) inertial mass as the ratio of force over acceleration · Newton's Third Law: equal and opposite forces between interacting objects · applying the Third Law to equilibrium situations · estimating speeds, accelerations, and forces for everyday road transport · required practical 7 (effect of varying force on acceleration at constant mass; effect of varying mass on acceleration at constant force)
Outcome
The student can state all three laws of motion, apply F = ma both ways, reason about balanced and unbalanced forces on vehicles and falling objects, carry out Required Practical 7, and (Higher Tier) explain inertia and inertial mass. (AQA 4.5.6.2)
Led by Leonhard Euler Simulacrum
The question
When a car moving at 30 miles per hour brakes to a stop, how far does it travel, and why does the distance quadruple rather than double when you go from 30 to 60?
Territory
stopping distance = thinking distance + braking distance · thinking distance during driver's reaction time · braking distance under braking force · greater speed → greater stopping distance (and braking distance grows with v²) · typical reaction time range 0.2–0.9 s · factors affecting reaction time: tiredness, drugs, alcohol, distraction · methods to measure human reaction time · factors affecting braking distance: adverse road conditions (wet, icy), poor tyre or brake condition, speed · work done by friction force in brakes reduces kinetic energy of vehicle · increase in brake temperature as kinetic energy is transferred to thermal energy · large decelerations cause brake overheating and loss of control · (HT) estimating forces in deceleration of road vehicles · (physics only) interpreting speed–stopping distance graphs · (physics only) estimating emergency stopping distances over typical speed ranges
Outcome
The student can define stopping distance, thinking distance, and braking distance, explain why each grows with speed (and why braking distance grows as the square of speed), identify the factors that affect reaction time and braking distance, explain the energy transfers during braking, and (Higher Tier) estimate the forces involved in typical road deceleration. (AQA 4.5.6.3)
Led by Joseph-Louis Lagrange Simulacrum
The question
A moving object carries a property called momentum, which is conserved even in a collision. What is this quantity, and what does its conservation let us predict?
Territory
momentum p = mv · units (kg·m/s) · conservation of momentum in a closed system · (physics only) calculations for collisions between two objects · (physics only) F = Δp/Δt · the equations F = ma and a = (v − u)/t combining to give F = m(Δv)/(Δt) · force as rate of change of momentum · applying the concept to safety features: airbags, seat belts, gymnasium crash mats, cycle helmets, cushioned playground surfaces · applying equations relating force, mass, velocity, and acceleration in interrelated ways · investigating collisions between laboratory trollies with light gates, data loggers, or ticker timers
Outcome
The student can apply p = mv, use conservation of momentum to solve collision problems, (physics only) apply F = Δp/Δt, and explain how safety features reduce peak force by extending the time over which momentum changes. (AQA 4.5.7)