Matthew Lam, Charling Li, Jasjit Manpotra

PERPETUAL MOTION SQUAD

When a large ball is dropped, with a smaller one stacked on top of it, onto a hard surface the

smaller ball will often rise much higher than it would if it was dropped onto the same surface by itself, while the larger ball hardly bounces at all.

Our aim was to investigate this phenomenon and design a multiple-ball system, using up to 4 balls, that will reach the greatest elevation of the top

ball.

PERPETUAL MOTION SQUAD

PERPETUAL MOTION SQUAD

PERPETUAL MOTION SQUAD

PERPETUAL MOTION SQUAD

Foam Balls

Nylon Monofilament

Retort Stand

Image source: Erlenmeyer Flasks

WD-40 Oil

Image source: wd-40.com

1 Kg Weight

Image source: Barr & Grosvenor Ltd

Known Data:The height the balls are dropped from are at 95 ± 2.5 cm.The masses of the four balls are:○ #1: 0.6 grams;○ #2: 1.2 grams;○ #3: 2.5 grams;○ #4: 4.0 grams.

Assumptions:Acceleration due to gravity is 9.8 m/s2.Air resistance is negligible.

PERPETUAL MOTION SQUADNote: In this presentation all units of measurement will be in centimetres.

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Before impact

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On impact

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Before impact

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PERPETUAL MOTION SQUAD

6 Sets of 2 trials 4-Ball system (Total mass 8.2 grams, Ratio of masses 6:12:25:40) Height dropped from: 97.17 cm Height Reached: 77.86 cm

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1, 2 & 3-Ball system (Total mass 4.3 grams, Ratio of masses 6:12:25) Height dropped from: 94.95 cm Height Reached: 48.40 cm

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1 & 2 -Ball system (Total mass 1.8 grams, Ratio of masses 1:2) Height dropped from: 94.33 cm Height Reached: 28.47 cm

PERPETUAL MOTION SQUAD

PERPETUAL MOTION SQUAD

PERPETUAL MOTION SQUAD

Astroblaster simulation program http://www.egtecno.com/applets/177/astroblaster-balls

PERPETUAL MOTION SQUAD

PERPETUAL MOTION SQUADNote: For these calculations, the coefficient of restitution is assumed to be 1.