VII. Translate the sentences paying attention to the verbs in Subjunctive Mood:

1. It is not essential that the stages in a step rocket be of increasing size.

2. If the bar magnet were broken in two, it would still retain its magnetism.

3. It should be understood that these diagrams have been calculated for a particular case. Other cases would give different results.

4. We all realize that if it were not for the friction between our shoes and the floor, we could not walk.

5. The scientific objectives may require that a space vehicle should maintain a fixed aspect with respect to the Earth, the Sun, the fixed stars or even a particular star.

6. If the Earth neither rotated nor revolved, one side would always have day and the other side would always have night.

7. In some calculations the air is treated as if it had no viscosity.

8. If the conductor had been moved slowly, the galvanometer deflection would have been smaller.

9. We have seen that electrons in crystals have wave properties as if they were in free space.

10. It is desirable that such power sources (nuclear batteries) should be ideally suited for a number of present-day applications that require power in remote places.

11. The whole weight of a body acts as though it were concentrated at a single point, this point being called the center of gravity.

12. The accuracy of launch velocity required for an orbit round the Moon is higher than might at first be supposed.

13. It is theoretically possible that a part of the nuclear energy might be liberated by transforming either the lightest or the heaviest of the elements into others of medium weight.

14. Without the Sun there would be no light, no heat, no energy of any kind.

15. Neutrons do not occur in nature and if they did, we could not accelerate them since they carry no electric charge.

16. It is necessary that the plates of a condenser be well insulated from another.

17. According to the law of gravitation, the force of gravity between the Earth and the Moon would be twice as great as it is, if the Moon were twice as massive as it is.

18. Without sunlight there would be no photosynthesis.

19. In the early twenties the suggestion that pictures could be transmitted even by wire, would have seemed fantastic to many people.

20. Life could not exist on the Earth but for the heat and light which it receives from the Sun.

21. Since the information from the probe which passed Venus had to be sent back no less than 36,000,000 miles to the Earth the achievement would have been regarded as impossible if it had not in fact occurred.

22. Ideally, the consumption of fuel would be minimized if the solar orbit of the vehicle were a transfer ellipse tangential to the Earth's orbit and that of the planet, the Earth and planet being on opposite sides of the Sun.

23. The solar constant is the quantity of energy, measured in calories, which would fall in one minute on an area of one square centimeter at the Earth's surface placed perpendicularly to the radiation, if the Earth had no atmosphere and was at its mean distance from the Sun.

24. The amount of gravitational energy which would have been released by the contraction of the Sun, for example, from an indefinitely great size to its present dimensions is readily calculable, and is found to amount to as much as would supply the present rate of radiation from the surface for 46.000,000 years.