miércoles, 10 de mayo de 2017
Ej p 92, 93, 94 and 95.
1. Copy and complete the following table in your notebook.
Types of structures Examples
Mass ----------- Walls, dams, etc.
Frame ----------- Structure of a building.
Truss ------------ Cranes, elecricity pylons etc.
Suspended --------- Suspension bridges, tents, etc.
2. Have you ever seen a structure thatr uses cables? Write down the names of the ones that
you can remember or the ones that you can see
and draw them in your notebook.
3.When a person sits on a chair, the stress that the chair has to withstand is due to the weight of the person, whereas the strength is the chair´s ability to withstand the load without breaking. Indicate wich i sthe strenght and wich is the strees in these two examples.
a) A wardrobe hanging from a rope.
b) A twisting telephone cord
6. Describe the structure of a turtle´s Shell. Why do you think it has this shape? What material do you think it is made from? Is it stronger enought for the stresses it has to withstand?
It has that shape to protect from predators. It is made of bones.
7. Which types of stressses de the following elements and activitieshave to support : a rope with a wheight hannging of it, a man puishing a cabinet, thingtening a screw, cutting our fingernails.
A rope with a wheight hangining off it-
A man pushing a cabinet-
Thingtening a scerew-
Cutting our finger nails-
9. Write a short description of three objects using one of the following adjectives for each object : rigid, elastic, and plastic. Explain how these properiesallow the objects to fulfil their funcion or make them suitable for their prupose.
Rigid- not pliant or flexible.
Elastic-deformed, compressed.
Plastic- group of synthetic or natural organic materials that may be shaped when soft and then hardened.
11. Copy and complete the following table in your notebook with objects that have propierties shown in the right-hand column
.
Objects Propierties
brick rigid
coffe cup defornable
rubber elastic
chewing gum plastic
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