AS Level Physics Revision Notes: Mechanics Complete Summary

Mechanics is a fundamental topic in AS Level Physics. This complete revision summary covers motion, forces, energy, momentum, and circular motion, providing all key concepts, essential formulas, and exam tips you need to excel in mechanics.

Motion

Kinematics

• Displacement, velocity, acceleration
• Distance-time and velocity-time graphs
• Equations of motion: v = u + at, s = ut + ½at², v² = u² + 2as
• Projectile motion

Key Formulas:

• v = u + at
• s = ut + ½at²
• v² = u² + 2as
• s = ½(u + v)t

Graphs:

• Distance-time: gradient = speed
• Velocity-time: gradient = acceleration, area = displacement

Forces and Newton’s Laws

Newton’s First Law

• Objects at rest stay at rest
• Objects in motion stay in motion
• Unless acted upon by unbalanced force
• Balanced forces: no acceleration

Newton’s Second Law

• F = ma
• Force causes acceleration
• Mass resists acceleration
• Units: N = kg m/s²

Newton’s Third Law

• Action and reaction pairs
• Equal and opposite forces
• Act on different objects
• Examples: walking, rocket propulsion

Free-Body Diagrams:

• Show all forces
• Identify direction
• Calculate resultant
• Apply Newton’s laws

Energy

Types of Energy:

• Kinetic: KE = ½mv²
• Potential: PE = mgh
• Elastic: stored in springs
• Internal: thermal energy

Energy Conservation:

• Energy cannot be created or destroyed
• Only transferred or transformed
• Total energy constant (isolated system)
• Work-energy theorem: W = ΔKE

Work and Power:

• Work: W = Fs cosθ
• Power: P = W/t = Fv
• Efficiency: useful output / total input
• Units: Joules (J), Watts (W)

Momentum

Momentum:

• p = mv
• Vector quantity
• Units: kg m/s
• Conservation of momentum

Collisions:

• Elastic: kinetic energy conserved
• Inelastic: kinetic energy not conserved
• Perfectly inelastic: objects stick together
• Momentum always conserved

Impulse:

• I = Ft = Δp
• Change in momentum
• Force-time graphs
• Applications: car safety, sports

Circular Motion

Centripetal Force:

• F = mv²/r
• Always toward center
• Not separate force
• Resultant of other forces

Angular Motion:

• Angular velocity: ω = v/r
• Period: T = 2π/ω
• Frequency: f = 1/T
• Centripetal acceleration: a = v²/r

Applications:

• Banked curves
• Vertical circles
• Orbits
• Centrifuges

Exam Tips

1. Know Your Formulas

• Learn all formulas
• Understand when to use each
• Show working
• Check units

2. Draw Diagrams

• Free-body diagrams essential
• Show all forces
• Label clearly
• Use correct symbols

3. Show Working

• Method marks crucial
• Show each step
• Check calculations
• Verify answers

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Use these revision notes as part of your comprehensive exam preparation. Combine with past paper practice and expert tutoring for best results.