1. An ideal rubber strains 1.10 times its original lenght at 27 centigrades(300 K)when supports strees of 150 lb/square inch. After ageing at air during 10 days at 127 centigrades of temperature , the stress force needed to get the enlargement of 1.10 times is 100 lb/square inch.If the original polymer contained 0.015 mol of molecular links per unit of volume. How much moles of links were loosed or gained by ageing effect?

2. An ideal rubber has a non linear strees- strain behaviour curve.If a cube of 1 cm of that rubber is compressed to 0.98 cm by a mass of 3 kg. What stress is requireed to strain a sample of this rubber until to get a new lengt of 7.5 cm?

3. How much work(J)is done in a natural rubber filament when strains slowly and non reversely to a= 2?
The initial slope of the stress- strain curve is 2 MPa and the volume of the rubber filament is 4.0 cubic centimeter.

4. One rubber filament strains until a lenght of 14 cm. Its original lenght is 4 cm. We found that the stress at this lenght has an increment of 330,000 Pa when the temperature increase 5 centigrades(from 25 to 30 centigrades). Which modulus must be expected to an elongation of 3% at 27 centigrades? We can neglect any volume change due by the temperature effect.