Unit 1: Mechanics and Materials

Use the uniformly accelerated motion equations in one dimension: s = (u + v)t/2, v = u + at, s = ut + ½at², and v² = u² + 2as.

Be able to draw and interpret displacement-time, velocity-time and acceleration- time graphs

Know the physical quantities derived from the slopes and areas of displacement- time, velocity-time and acceleration-time graphs, including cases of non-uniform acceleration and understand how to use the quantities

Understand scalar and vector quantities and know examples of each type of quantity and recognise vector notation

Be able to resolve a vector into two components at right angles to each other by drawing and by calculation

Be able to find the resultant of two coplanar vectors at any angle to each other by drawing, and at right angles to each other by calculation

Understand how to make use of the independence of vertical and horizontal motion of a projectile moving freely under gravity

Be able to draw and interpret free-body force diagrams to represent forces on a particle or on an extended but rigid body using the concept of centre of gravity of an extended body

Be able to use the equation ∑F = ma, and understand how to use this equation in situations where m is constant (Newton’s second law of motion), including Newton’s first law of motion where a = 0, objects at rest or travelling at constant velocity Use of the term ‘terminal velocity’ is expected.

Use gravitational field strength g = F/m and weight W = mg.

CORE PRACTICAL 1: Determine the acceleration of a freely-falling object

Know and understand Newton’s third law of motion and know the properties of pairs of forces in an interaction between two bodies

Understand that momentum is defined as p = mv

Know the principle of conservation of linear momentum, understand how to relate this to Newton’s laws of motion and understand how to apply this to problems in one dimension

Be able to use the equation for the moment of a force, moment of force = Fx where x is the perpendicular distance between the line of action of the force and the axis of rotation

Be able to use the concept of centre of gravity of an extended body and apply the principle of moments to an extended body in equilibrium

Be able to use the equation for work ∆W = F∆s, including calculations when the force is not along the line of motion

Use Ek = ½mv² for the kinetic energy of a body.

Be able to use the equation ∆Egrav = mg∆h for the difference in gravitational potential energy near the Earth’s surface

Know, and understand how to apply, the principle of conservation of energy including use of work done, gravitational potential energy and kinetic energy

Use P = E/t and P = W/t to relate power, time, energy transferred and work done.

Be able to use the equations useful energy output efficiency = total energy input and useful power output efficiency = total power input

1.4.23Density

Use density ρ = m/V.

1.4.24Upthrust and displaced fluid

Understand how to use the relationship upthrust = weight of fluid displaced

1.4.25Stokes’ law and viscosity

A be able to use the equation for viscous drag (Stokes’ Law), F = 6πηrv. b understand that this equation applies only to small spherical objects moving at low speeds with laminar flow (or in the absence of turbulent flow) and that viscosity is temperature dependent

1.4.26Core Practical 2 - viscosity by falling-ball method

CORE PRACTICAL 2: Use a falling-ball method to determine the viscosity of a liquid

1.4.27Hooke’s law

Be able to use the Hooke’s law equation, ∆F = k∆x, where k is the stiffness of the object

1.4.28Stress, strain and Young modulus

Understand how to use the relationships • (tensile or compressive) stress = force/cross-sectional area • (tensile or compressive) strain= change in length/original length Young modulus = stress/strain.

1.4.29Force-extension and force-compression graphs

A be able to draw and interpret force-extension and force-compression graphs b understand the terms limit of proportionality, elastic limit, yield point, elastic deformation and plastic deformation and be able to apply them to these graphs

1.4.30Stress-strain graphs and breaking stress

Be able to draw and interpret tensile or compressive stress-strain graphs, and understand the term breaking stress

1.4.31Core Practical 3 - Young modulus

CORE PRACTICAL 3: Determine the Young modulus of a material

1.4.32Elastic strain energy

Calculate elastic strain energy using ΔEel = ½FΔx and the area under a force–extension graph, including estimating areas for linear and non-linear graphs.