G481 Mechanics Revision Checklist

8/18/2019 G481 Mechanics Revision Checklist

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R e v i s i o n

AS Unit G481: Mechanics

Module 1 Motion1:1.1 Physical Quantities and Units

(a) explain that some physical quantities consist of a numericalmagnitude and a unit;(b) use correctly the named units listed in this specication asappropriate;(c) use correctly the following prexes and their symbols to indicatedecimal sub-multiples or multiples of units: pico (p), nano (n), micro (μ),milli (m), centi (c), ilo (), mega (!), giga ("), tera (#);(d) !ae suitable estimates of physical quantities included within this

specication$

1.1.2 Scalars and ectors

(a) dene scalar and vector quantities and gi%e examples;(b) draw and use a %ector triangle to determine the resultant of twocoplanar %ectors such as displacement, %elocity and force;(c) calculate the resultant of two perpendicular %ectors such asdisplacement, %elocity and force;(d) resol%e a %ector such as displacement, %elocity and force into twoperpendicularcomponents$

1.1.! "ine#atics

(a) dene displacement , instantaneous speed, average speed, velocityand acceleration;(b) select and use the relationshipsa%erage speed = distance & timeacceleration ' change in %elocity & timeto sol%e problems;

(c) apply graphical methods to represent displacement, speed, %elocityandacceleration;(d) determine %elocity from the gradient of a displacement against timegraph;(e) determine displacement from the area under a %elocity against timegraph;(f) determine acceleration from the gradient of a %elocity against timegraph$

1.1.4 $inear Motion

(a) deri%e the equations of motion for constant acceleration in a straight

line from a %elocity against time graph;


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(b) elect and use the equations of motion for constant acceleration in astraight line:

v = u + ats = ½ (u + v) / ts = ut + ½ at²v² = u² + 2 as

(c) apply the equations for constant acceleration in a straight line,including the motion of bodies falling in the arth*s uniform gra%itationaleld without air resistance;(d) explain how experiments carried out by "alileo o%erturned +ristotle*sideas of motion;(e) describe an experiment to determine the acceleration of free fall gusing a falling body;(f) apply the equations of constant acceleration to describe and explainthe motion of an obect due to a uniform %elocity in one direction and aconstant acceleration in a perpendicular direction$

Module 2 1.2 %orces in Action1.2.1 %orce

(a) ol%e problems using the relationship: net force ' mass acceleration (F = ma)appreciating that acceleration and the net force are always in the samedirection;(b) dene the newton;(c) apply the equations for constant acceleration and F ' ma to analysethe motion of obects;(d) recall that according to the special theory of relati%ity, F ' ma cannotbe used for a particle tra%elling at %ery high speeds because its massincreases$

1.2.2 Non& $inear Motion(a) explain that an obect tra%elling in a .uid experiences a resisti%e or africtional force nown as drag;(b) state the factors that a/ect the magnitude of the drag force;(c) determine the acceleration of an obect in the presence of drag;(d) state that the weight of an obect is the gra%itational force acting onthe obect;(e) select and use the relationship: weight ' mass acceleration of freefall(W = mg);(f) describe the motion of bodies falling in a uniform gra%itational eld

with drag;(g) use and explain the term terminal velocity $

1.2.! '(uili)riu#

(a) draw and use a triangle of forces to represent the equilibrium of threeforces acting at a point in an obect;(b) state that the centre of gravity of an obect is a point where the entireweight of an obect appears to act;(c) describe a simple experiment to determine the centre of gra%ity of anobect;(d) explain that a couple is a pair of forces that tends to produce rotation


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only;where F is the force normal to the area A$(e) dene and apply the torque of a couple;(f) dene and apply the moment of force;(g) explain that both the net force and net moment on an extendedobect in equilibrium is 0ero;(h) apply the principle of moments to sol%e problems, including thehuman forearm;

(i) select and use the equation for density: 1 ' m& 2 ;

() select and use the equation for pressure p= F/Awhere F is the force normal to the area A$

1.2.4 *ar Sa+ety

(a) dene thinking distance, braking distance and stopping distance;(b) analyse and sol%e problems using the terms thining distance,braing distance and stopping distance;(c) describe the factors that a/ect thining distance and braingdistance;(d) describe and explain how air bags, seat belts and crumple 0ones incars reduce impact forces in accidents;

(e) describe how air bags wor, including the triggering mechanism;(f) describe how the trilateration technique is used in "3 (globalpositioning system) for cars$

Module ! 1.! ,or- and 'nery1.!.1 ,or- and *onservation o+ 'nery

(a) dene work done by a force;(b) dene the joule;(c) calculate the wor done by a force using W = Fx and W ' Fx cos 4;(d) state the principle of conser%ation of energy;

(e) describe examples of energy in di/erent forms, its con%ersion andconser%ation, and apply the principle of energy conser%ation to simpleexamples;(f) apply the idea that wor done is equal to the transfer of energy tosol%e problems$

1.!.2 "inetic and Potential 'neries

(a) select and apply the equation for inetic energy E ' 5mv²(b) apply the denition of wor done to deri%e the equation for thechange in gra%itational potential energy;(c) select and apply the equation for the change in gra%itational potentialenergy near the arth*s surface E p ' mgh;(d) analyse problems where there is an exchange between gra%itationalpotentialenergy and inetic energy;(e) apply the principle of conser%ation of energy to determine the speedof an obect falling in the arth*s gra%itational eld$

1.!.! Po/er

(a) dene power as the rate of wor done;(b) dene the watt ;

(c) calculate power when sol%ing problems;


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(d) state that the e6ciency of a de%ice is always less than 7889 becauseof heat losses;(e) select and apply the relationship for e6ciencyefficiency ' useful output energy / total input energy 7889(f) interpret and construct aney diagrams$

1.!.4 0ehaviour o+ Srins and Materials

(a) describe how deformation is caused by a force in one dimension and

can be tensile or compressi%e;(b) describe the beha%iour of springs and wires in terms of force,extension, elastic limit, ooe*s law and the force constant (ie force perunit extension or compression);(c) select and apply the equation F = kx, where k is the force constant ofthe spring or the wire;(d) determine the area under a force against extension (or compression)graph to nd the wor done by the force;(e) select and use the equations for elastic potential energy

E ' 5 Fx and E ' 5kx² (f) dene and use the terms stress, strain, Young modulus and ultimatetensile strength (breaking stress);

(g) describe an experiment to determine the oung modulus of a metal inthe form of a wire;(h) dene the terms elastic deformation and plastic deformation of amaterial;(i) describe the shapes of the stress against strain graphs for typicalductile, brittle and polymeric materials$

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G481 Mechanics Revision Checklist