A-level Physics₇₄₀₈

Nature of scalars and vectors.

Examples should include:

velocity/speed, mass, force/weight, acceleration, displacement/distance.

Addition of vectors by calculation or scale drawing.

Calculations will be limited to two vectors at right angles. Scale drawings may involve vectors at angles other than $\mathrm{90}$ °.

Resolution of vectors into two components at right angles to each other.

Examples should include components of forces along and perpendicular to an inclined plane.

Problems may be solved either by the use of resolved forces or the use of a closed triangle.

Conditions for equilibrium for two or three coplanar forces acting at a point. Appreciation of the meaning of equilibrium in the context of an object at rest or moving with constant velocity.

MS 0.6, 4.2, 4.4, 4.5 / PS 1.1

Investigation of the conditions for equilibrium for three coplanar forces acting at a point using a force board.

Moment of a force about a point.

Moment defined as force × perpendicular distance from the point to the line of action of the force .

Couple as a pair of equal and opposite coplanar forces.

Moment of couple defined as force × perpendicular distance between the lines of action of the forces .

Principle of moments.

Centre of mass.

Knowledge that the position of the centre of mass of uniform regular solid is at its centre.

Displacement, speed, velocity, acceleration.

$\mathit{v}\mathsf{=}\frac{\mathsf{∆}\mathit{s}}{\mathsf{∆}\mathit{t}}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}\mathit{}$

$\mathit{a}\mathsf{=}\frac{\mathsf{∆}\mathit{v}}{\mathsf{∆}\mathit{t}}$

Calculations may include average and instantaneous speeds and velocities.

Representation by graphical methods of uniform and non-uniform acceleration.

Significance of areas of velocity–time and acceleration–time graphs and gradients of displacement–time and velocity–time graphs for uniform and non-uniform acceleration eg graphs for motion of bouncing ball.

Equations for uniform acceleration:

$\mathit{v}\mathsf{=}\mathit{u}\mathsf{+}\mathit{a}\mathit{t}$

$\mathit{s}\mathsf{=}\left(\frac{\mathit{u}\mathsf{+}\mathit{v}}{\mathsf{2}}\right)\mathit{t}$

$\mathit{ }\mathit{s}\mathsf{=}\mathit{u}\mathit{t}\mathsf{+}\frac{\mathit{a}{\mathit{t}}^{\mathsf{2}}}{\mathsf{2}}$

${\mathit{v}}^{\mathsf{2}}\mathsf{=}{\mathit{u}}^{\mathsf{2}}\mathsf{+}\mathsf{2}\mathit{a}\mathit{s}$

Acceleration due to gravity, $\mathit{g}$ .

Distinguish between instantaneous velocity and average velocity.

MS 3.5, 3.6

Measurements and calculations from displacement–time, velocity–time and acceleration–time graphs.

MS 0.5, 2.2, 2.3, 2.4

Calculations involving motion in a straight line.

Required practical 3 : Determination of $\mathit{g}$ by a freefall method.

Students should be able to identify random and systematic errors in the experiment and suggest ways to remove them.

MS 3.9

Determine $\mathit{g}$ from a graph.

Independent effect of motion in horizontal and vertical directions of a uniform gravitational field. Problems will be solvable using the equations of uniform acceleration.

Qualitative treatment of friction.

Distinctions between static and dynamic friction will not be tested.

Qualitative treatment of lift and drag forces.

Terminal speed.

Knowledge that air resistance increases with speed.

Qualitative understanding of the effect of air resistance on the trajectory of a projectile and on the factors that affect the maximum speed of a vehicle.

PS 2.2, 3.1

Investigation of the factors that determine the motion of an object through a fluid.

Knowledge and application of the three laws of motion in appropriate situations.

$\mathit{F}\mathsf{=}\mathit{m}\mathit{a}$ for situations where the mass is constant.

PS 4.1 / MS 0.5, 3.2 / AT a, b, d

Students can verify Newton’s second law of motion.

MS 4.1, 4.2

Students can use free-body diagrams.

$\mathit{mome}\mathit{n}\mathit{tum}\mathsf{=}\mathit{mass}\mathit{}\mathsf{\times }\mathit{}\mathit{velocity}$

Conservation of linear momentum.

Principle applied quantitatively to problems in one dimension.

Force as the rate of change of momentum, $\mathit{F}\mathsf{=}\frac{\mathsf{∆}\left(\mathit{m}\mathit{v}\right)}{\mathsf{∆}\mathit{t}}$

Impulse = change in momentum

$\mathit{F}\mathrm{∆}\mathit{t}\mathsf{=}\mathsf{∆}\left(\mathit{m}\mathit{v}\right)$ , where $\mathit{F}$ is constant.

Significance of the area under a force–time graph.

Quantitative questions may be set on forces that vary with time. Impact forces are related to contact times (eg kicking a football, crumple zones, packaging).

Elastic and inelastic collisions; explosions.

Appreciation of momentum conservation issues in the context of ethical transport design.

MS 2.2, 2.3

Students can apply conservation of momentum and rate of change of momentum to a range of examples.

Energy transferred, $\mathit{W}\mathsf{=}\mathit{F}\mathit{s}\cos \mathsf{}\mathit{\theta }$

$\mathit{rate\; of\; doing\; work}\mathsf{=}\mathit{rate\; of\; energy\; transfer}\mathsf{,}\mathit{ }\mathit{ }\mathit{P}\mathsf{=}\frac{\mathsf{∆}\mathit{W}}{\mathsf{∆}\mathit{t}}\mathsf{=}\mathit{F}\mathit{v}$

Quantitative questions may be set on variable forces.

Significance of the area under a force–displacement graph.

$\mathit{efficiency}\mathsf{=}\frac{\mathit{useful\; output\; power}}{\mathit{input\; power}}$

Efficiency can be expressed as a percentage.

MS 0.3 / PS 3.3, 4.1 / AT a, b, f .

Investigate the efficiency of an electric motor being used to raise a mass through a measured height. Students should be able to identify random and systematic errors in the experiment and suggest ways to remove them.

Principle of conservation of energy.

$\mathrm{∆}{\mathit{E}}_{\mathrm{p}}\mathsf{=}\mathit{m}\mathit{g}\mathrm{∆}\mathit{h}$ and ${\mathit{E}}_{\mathrm{k}}\mathsf{=}\frac{\mathsf{1}}{\mathsf{2}}\mathit{m}{\mathit{v}}^{\mathsf{2}}$

Quantitative and qualitative application of energy conservation to examples involving gravitational potential energy, kinetic energy, and work done against resistive forces.

MS 0.4, 2.2

Estimate the energy that can be derived from food consumption.

Density, $\mathit{\rho }\mathsf{=}\frac{\mathit{m}}{\mathit{V}}$

Hooke’s law, elastic limit,

$\mathit{F}\mathsf{=}\mathit{k}\mathrm{∆}\mathit{L}$ , $\mathit{k}\mathit{ }$ as stiffness and spring constant.

Tensile strain and tensile stress.

Elastic strain energy, breaking stress.

$\mathit{energy}\mathit{ }\mathit{stored}\mathsf{=}\frac{\mathsf{1}}{\mathsf{2}}\mathit{F}\mathrm{∆}\mathit{L}\mathsf{=}\mathit{area\; under\; force-extension\; graph}$

Description of plastic behaviour, fracture and brittle behaviour linked to force–extension graphs.

Quantitative and qualitative application of energy conservation to examples involving elastic strain energy and energy to deform.

Spring energy transformed to kinetic and gravitational potential energy.

Interpretation of simple stress–strain curves.

Appreciation of energy conservation issues in the context of ethical transport design.

MS 0.2, 4.3 / PS 3.3, 4.1

Students can compare the use of analogue and digital meters.

MS 0.4, 4.3 / AT e

Estimate the volume of an object leading to an estimate of its density.

$\mathit{Young\; modulus}\mathsf{=}\frac{\mathit{tensile\; stress}}{\mathit{tensile\; strain}}\mathsf{=}\frac{\mathit{F}\mathit{L}}{\mathit{A}\mathsf{∆}\mathit{L}}$

Use of stress–strain graphs to find the Young modulus.

(One simple method of measurement is required.)

MS 3.1

Required practical 4: Determination of the Young modulus by a simple method.