Coaching Centre
Module 2: Dynamics Notes
How forces change motion: Newton’s laws, work and energy, power, and momentum in collisions.
Sections
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2A Forces and free-body diagrams Mastered
Forces as interactions between two objects, contact and non-contact forces, Newton's three laws of motion, third-law pairs, weight and the normal force, apparent weight in a lift, and how to draw a free-body diagram.
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2B Net force and components Mastered
Finding the net force on an object by algebraic addition in one dimension, vector addition (tip to tail) in two dimensions, and resolving forces into perpendicular components with F cos θ and F sin θ; the resultant and the equilibrant.
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2C Equilibrium Mastered
Static and dynamic equilibrium, the condition that the net force is zero, solving equilibrium problems in one and two dimensions with components and with a closed triangle of forces, and why tension rises sharply as cables flatten.
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2D Inclined planes Mastered
Resolving weight parallel and perpendicular to a slope, the normal force on an incline, the angle at which an object starts to slide, acceleration down a rough slope, and the mandatory inclined-plane practical with light gates to find the coefficient of friction.
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2E Friction and resistance forces Mastered
Static and kinetic friction and their coefficients, friction = μN, how friction depends on the normal force, applying Newton's first and second laws with friction, rolling resistance, air resistance and terminal velocity.
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2F Constant net force and connected bodies Mastered
Motion under a constant net force described with words, graphs and vectors; Newton's second law for connected bodies (cart and hanging mass, Atwood machine, towing); tension in strings; and the F = ma practical with constant total mass.
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2G Work and kinetic energy Mastered
Work done by a force (W = Fs cos θ), positive, negative and zero work, work as the area under a force–displacement graph, kinetic energy, and the work–energy theorem W = F_net s = ΔK.
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2H Conservation of mechanical energy Mastered
Gravitational potential energy near Earth's surface (ΔU = mgΔh), conservation of mechanical energy for falling objects, slides, pendulums and roller coasters, energy losses to friction, and choosing between the energy and force methods.
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2I Power Mastered
Power as the rate of energy transfer (P = ΔE/t), power and velocity (P = Fv), efficiency, the power needed to overcome air resistance and rolling resistance at different speeds, and a practical to measure personal power output.
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2J Conservation of momentum Mastered
Momentum as a vector, Newton's second law in terms of momentum, why momentum is conserved in a closed system, one-dimensional collisions and explosions, two-dimensional collisions solved with components, and the momentum practical.
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2K Impulse and car safety Mastered
Impulse as FΔt = Δp, impulse as the area under a force–time graph, average and peak forces in collisions, extending collision time in sport and safety equipment, and evaluating crumple zones, seatbelts and airbags.
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2L Elastic and inelastic collisions Mastered
Classifying collisions as elastic, inelastic or completely inelastic by comparing kinetic energy before and after, where the lost kinetic energy goes, one-dimensional elastic collisions, Newton's cradle, and the two-stage analysis of the ballistic pendulum.
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2M Dynamics review Mastered
A summary of Module 2 Dynamics, how forces, energy and momentum connect, the key equations, key words, and a mixed HSC-style test covering Newton's laws, equilibrium, inclined planes, friction, connected bodies, work, energy, power, momentum, impulse and collisions.