Ford class aircraft carriers.  In this design the aircraft is accelerated by a linear induction motor where the applied force and acceleration can be varied accurately. This allows for smoother acceleration as compared to steam catapults and permits very light aircraft such as UAV to be launched off of aircraft carriers, a feat which it not possible with standard steam catapults. Linear induction motors work similarly to a standard induction motors except that the stator has been un-winded and runs the length of the track. The rotor, instead of being spun around its central axis is rather pulled along the stator by a moving magnetic field.
The inside of the tube is smooth, and there are no surfaces for pressure to push on in a forward (or aft) direction. Because air flowing into the tube is slowed and compressed, it acts as drag working against motion through the air. This added drag consumes some of the power from the engine propelling the tube. The thrust from the exhaust gasses pushes forward against the compressed air at the front of the tube. This reduces the energy that the engine moving the tube has to expend, so the tube can move faster.
This difference is what allows the slower moving air to push up against the bottom of the wing with greater force than the faster moving air is pushing down against the top of the wing. In level flight, this upward force is just enough to counteract the downward force caused by
Renewable energy are considered to be important in improving the security of energy supplies by decreasing the dependence on fossil fuels and in reducing the emissions of greenhouse gases. The viability of isolated systems using renewable energy depends largely on regulations and stimulation measures. Renewable energy are the natural energy re that are inexhaustible, for example, wind, solar, geothermal, biomass, and small hydro generation. Among the renewable energy , small hydro and wind energy have the ability to complement each other. In a location with enough average wind speed and a suitable area for wind turbines, wind pumped storage system is a good combination with a hydro power plant.
There are two problems with this. One is the more weight the fly wheel has, the more dangerous it is because it is a larger amount of potential energy that could be released in an uncontrolled environment. It has a 1:1 increase of power (mass) as the weight of the fly wheel increases, the power output increases by that same amount. Our fly wheel is made out of carbon fiber which is considerably lighter than their steel ones. When that fails, the flywheel turns to dust thus there is no potential danger from steel fragments.
Environmental protection and no need to get fossil fuels to generate electricity; (b). Occupied less space than normal power station. The surrounding land of the wind turbine can be used for agriculture； （c）. New technology makes the extraction of wind energy much more efficient； （d）. Wind turbines are the great resource to generate energy everywhere such as mountain and countryside； （e）.
In the lab, the friction still affect the experiment a lot. There are two different frictions affect our Atwood’s machine which is the air frictions and frictions of pulleys. In the dictionary, the air friction is the force that in the opposition to the relative motion which is act on the object as it passes though the air. (What is air
What happens is that since the air on the land takes less time to heat up than the air on the ocean, the warm air on the land starts to rise and expand. As the warm air rises the cold air flows into its place as, hence creating a flow of air, which is wind. During the night the opposite happens. The air on the land cools down faster than the air on the water, the same process occurs and wind is again created, meaning that a wind turbine can be used day and night. The only necessary condition for wind turbines to work is that there is wind, which turns the blades.