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Activity 1

The experiment was set up between two school woodwork benches, as shown in the photograph. Each experiment was repeated three times and the results averaged.

School woodwork benches

Results

With the ice-cream stick on edge:

Attempt Result (L)

1 8.5

2 8.25

3 8.75

Average = 8.5 L
But since 1 litre of water has a mass of 1 kg
M = 8.5 kg
F = 85 N
With the ice-cream stick laying flat:

Attempt Result (L)

1 2.0

2 2.2

3 2.1

Average = 2.1 litres
But since 1 litre of water has a mass of 1 kg
M = 2.1 kg
F = 21 N

Attempt	Result (L)
1	8.5
2	8.25
3	8.75

Attempt	Result (L)
1	2.0
2	2.2
3	2.1

Conclusion

By simply changing the orientation of a beam we can significantly alter its ability to withstand forces. In the case of the ice-cream sticks the one on its edge is capable of holding a force four times as great as the one laying flat.

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Activity 2

Bending moment diagram

Calculation of moment of inertia

Calculation of bending stress

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