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The smooth sides and rounded outline of the shape do not disturb the flow of water and do not cause turbulence behind the object. Turbulence causes drag in a vehicle. The hulls of vehicles that are immersed in water are streamlined so that the vehicles can sail faster through the water. The center of gravity of the vehicles in water must be below the water level so that the vehicle is stable and balanced when moving on water..

23

The use of nuclear energy to generate electrical energy is a controversial issue in many countries but over half of the electricity in France is generated by nuclear power stations..People are against the production of nuclear energy because past nuclear – related tragedies still haunt them. The effects caused by nuclear disasters such as Chernobyl and Three Mile Island are still fresh in the minds of most people.