PROBLEM SOLVING

Date: 2015-10-07; view: 551.

Physical; many; what ;suspension; natural; concrete; bridge; stress; use; how; mechanical; amplitude; example; disaster; phenomenon; rate

Resonance

Resonance is an important (1)......................phenomenon that can appear in a great (2)..........................different situations. A tragic example is the Tacoma Narrows bridge disaster. This (3).........................bridge in Washington State, collapsed in a mild gale on 1 July 1940. The wind set up oscillating around the (4)... which vibrated more and more violently until it broke up under the (5).........................The bridge had been in (6)........................for just four months; engineers learnt a lot about (7)..........................oscillations can build up when a (8)........................... structure is subject to repeated forces. You will have observed a much more familiar (9)......................of resonance when pushing a small child on a swing; swing and child have a natural frequency of oscillation; a small push each swing results in the (10)........................increasing until the child swinging high in the air.

Task one: Sentence building

From the prompts given, build up meaningful sentences; you can add any necessary material.

1. there/ be/ two/ system/ measurement/ use/ today.

…………………………………………………………………………………….

2. certain/ physical/ quantity/ be/ choose/ base quantities/ each/ be/ define/ in terms of/standard.

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3. Physics/ be/ base/ measurement.

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4. describe/physical/quantity/we/first/define/unit.

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5. there/be/so/many/that/physical/quantity/it/be/problem/organize/them.

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6. many/SI/derive/unit/be/define/terms/seven/base units.

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7. SI/ standard/mass/be/platinum-iridium/cylinder/keep/International Bureau of Weights and Measures/ near/Paris/assign/, /international agreement/mass/, /one kilogram.

…………………………………………………………………………………….

…………………………………………………………………………………….

8. conversion/units/one/system/another/may/be/perform/use/chain-link conversions.

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9. unit/time/be/formerly/define/in terms of/rotation/the Earth.

…………………………………………………………………………………….

10. atomic/scale/atomic/mass/unit/define/in terms of/atom/carbon-12/be/usually/use.

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Task two: Sentences transformation

Rewrite each of the following sentences in the way that its meaning retains.

1. If we divide the mass of a substance by its density, we obtain its volume.

To……………………………………………………………………………….....

2. Time, mass, and length are the most important fundamental units.

The ………………………………………………………………………………..

3. The basic concepts of the thermodynamics are easily understood in terms of

experiments.

With…………………………………………………………………………….....

4. An atom is the smallest particle that can not be split up in a chemical action.

The ………………………………………………………………………………..

5. In a liquid, the depth and the pressure are in direct proportion.

In a liquid,………………………………………………………………………....

6. The emission of alpha and beta particles causes a change in the atom.

A change…………………………………………………………………………..

7. Each radioactive element has a fixed rate of decay called half-life.

The half-life……………………………………………………………………......

8. Fast moving α particles could split the nucleus of an atom.

The nucleus………………………………………………………………………..

9. Lightweight nuclei can be combined into heavier nuclei.

Heavier nuclei……………………………………………………………………..

10. Cadmium absorbs neutrons, so cadmium robs are inserted or removed to control

reaction.

As ………………………………………………………………………………....