Mechanics and Materials

Worked examples (10)

• 1Average speed vs average velocity (3 marks)
• 2Free fall from rest: finding the final velocity (2 marks)
• 3Resolving a force into components (3 marks)
• 4Displacement of an accelerating car (3 marks)
• 5Using v² = u² + 2as (no time given) (3 marks)
• 6Displacement from a velocity–time graph (4 marks)
• 7Determining g from an s–t² graph gradient (4 marks)
• 8Range of a projectile launched at an angle (6 marks)
• 9Horizontal launch from a cliff (6 marks)
• 10Maximum height of a vertically thrown ball (6 marks)

Model answers (9)

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• ✓Model answer 6
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1 (Core Practical 1)
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1

Worked examples (10)

• 1Calculating the moment of a force (2 marks)
• 2Finding the force from a required moment (2 marks)
• 3Balancing a seesaw using the principle of moments (3 marks)
• 4Moment of a force applied at an angle (3 marks)
• 5Reaction forces on a loaded shelf (4 marks)
• 6Show that — second reaction by resolving forces (4 marks)
• 7Centre of gravity of a non-uniform plank (4 marks)
• 8Ladder against a wall — taking moments about the foot (5 marks)
• 9Hinged beam supported by a cable (5 marks)
• 10Moment of a couple on a steering wheel (3 marks)

Model answers (9)

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• ✓Model answer 8
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1

Worked examples (10)

• 1Calculating density from mass and volume (2 marks)
• 2Converting g cm⁻³ to kg m⁻³ (2 marks)
• 3Upthrust as weight of fluid displaced (3 marks)
• 4Will it float? Comparing densities (4 marks)
• 5Viscous drag from Stokes' law (3 marks)
• 6Terminal velocity of a falling sphere (4 marks)
• 7Core Practical 2 — viscosity from a falling ball (4 marks)
• 8Fraction of a floating object submerged (5 marks)
• 9Charged oil drop falling at terminal velocity (5 marks)
• 10Why warmer liquid gives a faster ball (3 marks)

Model answers (9)

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• ✓Model answer 8
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1 / Core Practical 2

Worked examples (10)

• 1Calculating weight from mass (2 marks)
• 2Momentum of a moving car (2 marks)
• 3Spotting a Newton's third-law pair (3 marks)
• 4Resultant force and acceleration (3 marks)
• 5Impulse and the force on a struck ball (4 marks)
• 6A perfectly inelastic collision (4 marks)
• 7Conservation of momentum with a rebound (5 marks)
• 8Show that terminal velocity occurs when forces balance (4 marks)
• 9Testing whether a collision is elastic (6 marks)
• 10Explain conservation of momentum from Newton's laws (6 marks)

Model answers (9)

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• ✓Model answer 9

Worked examples (10)

• 1Work done by a horizontal force (2 marks)
• 2Kinetic energy of a moving object (2 marks)
• 3Gain in gravitational potential energy (3 marks)
• 4Work done by a force at an angle (3 marks)
• 5Speed of a falling object from energy (3 marks)
• 6Power from energy and time (3 marks)
• 7Engine power for a car up an incline (4 marks)
• 8Energy dissipated by friction on a slope (4 marks)
• 9Efficiency of a motor (3 marks)
• 10'Show that' — power output of a turbine (4 marks)

Model answers (9)

• ✓Model answer 1
• ✓Model answer 2
• ✓Model answer 3
• ✓Model answer 4
• ✓Model answer 5
• ✓Model answer 6
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1
• ✓Model answer 8
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1

Worked examples (10)

• 1Force constant from force and extension (2 marks)
• 2Extension from a known force constant (2 marks)
• 3Tensile stress in a wire (3 marks)
• 4Tensile strain in a stretched wire (2 marks)
• 5Young modulus of a wire (4 marks)
• 6Elastic strain energy stored in a spring (3 marks)
• 7Identifying material behaviour from a graph (3 marks)
• 8Show that the Young modulus is about 1.2 × 10¹¹ Pa (4 marks)
• 9Extension and strain energy of a loaded wire (5 marks)
• 10Uncertainty in the Young modulus (Core Practical 3) (4 marks)

Model answers (9)

• ✓Model answer 1
• ✓Model answer 2
• ✓Model answer 3
• ✓Model answer 4
• ✓Model answer 5
• ✓Model answer 6
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1 Core Practical 3
• ✓Model answer — Adapted from Edexcel IAL Physics Unit 1
• ✓Model answer 9