Takel, Jan van Musschenbroek Leiden, c. 1720-1740?

V09257

Takel

Gravesande, Willem Jacob 's (Ontwerper)‎, Musschenbroek, Jan van (Maker)‎, Whiston, William (Ontwerper)‎

1720 - 1740

Tweemaal drie messingen katrollen van aflopende omvang, verticaal geschakeld. Houten statief (50 x 10 x 14)Kwam ook al voor in de vroeger edities van 's Gravesandes boek (1720: Tab. VI, fig. 5, 1725: Tab. VII, fig. 5) en in Whiston's A Course of Mathematical Lectures and Experiments (1714), Tab. III, fig. 6. Identificatie in 's Gravesandes privékabinet is niet eenduidig; wellicht is het de 'twee blokke elk van drie katrollen' (f 12). Het kàn echter ook afkomstig zijn uit de leverantie van Jan Paauw jr. in 1759: '4 zware koperen takels ieder van 6 schijven à f 18-10 [per stuk]' (AC I 51). Het statief is van later datum, waarschijnlijk ca. 1840 (voor argument zie 9256).

Hoogte: 35 cm
Breedte: 5.5 cm
Diepte: 1 cm
statief Hoogte: 51 cm
Breedte: 14.5 cm
Diepte: 10.5 cm

Tackles and pulleys are practical instruments, for instance to hoist heavy objects. In physics tackles are also very instructive, especially in the area of forces. This was the reason professor 's Gravesande bought them for his cabinet. With the help of a combination of pulleys he showed his students that the force needed to lift an object can be diminished. With two pulleys you only need half the force. So in order to lift 10 kg, you only need the force for lifting 5 kg, when you use a combination of two pulleys.

This special tackle combines six pulleys. Therefore the force needed to lift an object is six times smaller than its weight. The backside of the story is that you must hoist six times more rope. The total amount of work stays the same, but you can do it with more ease.

Literature
W.J. 's Gravesande, Physices Elementa Mathematica (Leiden 1720), Tab. VI, fig. 5
Peter de Clercq, The Leiden Cabinet of Physics (Leiden 1997)

(BOERH f 2248) W.J. 's Gravesande, Physices Elementa Mathematica (Leiden 1725-1721), par. 266 en Tab. IX, fig. 5.
Peter de Clercq, The Leiden Cabinet of Physics, a descriptive Catalogue, p. 26

Paauw, Jan; Leiden

03.01.0 Statica (onderwerp)
Leiden; the Netherlands (geografie)

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