Question

Problem 10 (3%) Plywood is made by bonding together thin layers of wood in such a way that the angle between grains of an layer to grains of adjacent layers is B. 300 C. 450 D. 900 E. None of the above Problem 11 (3%) Anisotropic materials are the materials with: A. similar properties along all directions B. different properties along different directions C. high modulus of rapture D. uniform cross-sectional area E. None of the above

Answer 1

10) “D” -In plywood, the grains in one layer are perpendicular to the grains in adjacent layers i.e., the grains in any layer are at an of 90⁰ to the adjacent layer. This is because of the reason when the grains tend to shrink in one direction, the grains in the adjacent layer which are perpendicular tries to prevent the shrinkage. It is also one of the reason for strength of the plywood.

11) “B”- Anisotropic materials have different properties along different directions.