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The use of free body diagrams as an essential tool for the analysis of problems in statics is examined.
Metadata describing this Open University video programme
Module code and title: T232, Engineering mechanics: solids
Item code: T232; 02
First transmission date: 30-03-1980
Published: 1980
Rights Statement:
Restrictions on use:
Duration: 00:24:00
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Producer: Martin Wright
Contributors: Tony Bright; John Dixon; Roger Gibson
Publisher: BBC Open University
Keyword(s): Engineering mechanics; Mechanics; Spring and block; Static forces
Footage description: Shots of a rotating link mechanism and then of the same mechanism with another link added which locks the structure. Tony Bright introduces the programme. Shots of a railway gantry and of a collapsed bridge. Roger Gibson, in the studio, looks at a pin-jointed structure. He points out some, but not all, of the forces acting on the structure. A series of animations illustrate, briefly, some of the forces involved in engineering problems; buoyancy, elasticity, gravity and friction. Roger Gibson and John Dixon examine the properties of elastic forces with the aid of animations and blocks suspended from springs. Using a free body diagram, Dixon calculates the forces acting on the spring and block. He goes on to explain the difference between weight and mass. Roger Gibson, with the aid of an animated free body diagram, examines the effect of friction on a body standing on a slope. He then uses a spring and block to show that when a certain force is applied, the limiting condition is reached and the block begins to move down the slope. John Dixon examines hydrostatic forces by performing an experiment which demonstrates the principles of fluid displacement and buoyancy. Animated diagrams are also shown to help illustrate points made. Roger Gibson places weights on a stiff spring taken from a pin-jointed structure which has had strain gauges attached to it. In this way he obtains readings from gauges for each increment of weight added which allows him to calibrate the spring. He explains that he can use this calibration to do calculations for the structure as a whole. Gibson goes on to analyse the complete structure. He hangs weights from the structure and then uses the ideas of free body diagrams and equilibrium to work out the forces acting on two members within the structure. An animated diagram is superimposed over the structure at intervals. Finally Gibson compares the values of forces for the two members which were calculated above with values obtained experimentally using strain gauges. Tony Bright sums up the programme.
Master spool number: HOU3371
Production number: FOUT063X
Videofinder number: 2233
Available to public: no