That's the plural of the letter "T".

It happens because very much energy is generated by using fossil fuels - coal, oil and gas.

At the power plant steam turbines drive the generators, and the steam is made from pure water in boilers that burn the fuel. The burning process is what creates carbon dioxide and the heat comes from the formation of the chemical bonds between carbon and oxygen when carbon dioxide is formed from the carbon in the fuel and the oxygen from the air.

So conserving electrical energy means that less CO2 is produced.

When you switch an appliance off in your home, the local power plant starts to speed up ever so slightly, and the automatic throttle causes the boiler to produce slightly less steam to keep the speed constant. Therefore whenever you switch something off the power plant gives off CO2 at a slightly slower rate, almost immediately.

One example is an incandescent light bulb. We normally use it for light, but it also generates a lot of heat.

A change in the velocity is produced by a force acting on the object. A change in velocity means a change in speed or direction (or both).

Yes because the energy stored in the bow (ideally) is the force times the distance. 1 metre drawn against a force of 100 pounds (445 Newtons) gives a potential energy of 445 Joules.

That energy converted totally into kinetic energy in a half-pound arrow could propel it at 44 metres/sec, or 98 mph.

Conversions of energy forms are lossy. For example, when mechanical energy is converted to electrical energy (such as happens in an electric generator), there is friction which leads to the escape of heat and sound energy. While the total amount of energy in all forms remains constant, the heat and sound energy are next to impossible to recapture, so this is considered a loss of useful energy.

The actual amount depends on your specific energy bill, but you could save anywhere between 5% to 15 % of the total cost.

If you mean for a steam engine, probably not. At a lower pressure, the temperature will also be lower (the boiling point is dependent on the pressure), and according to Carnot's equation, the maximum theoretical efficiency will be less in that case.

That is potential energy when the water is sitting in the dam. The PE is converted into kinetic energy by running the water down a chute to allow it to gain speed, and then it hits the turbine blades to turn the turbine which drives a generator.

Because of Newton's 3rd law, if you push on a wall with, let's say, 10 N, the wall will, by definition of the law, push back on you with 10N. The forces are balanced and you don't move backwards because the forces "cancel out" because they are equal and opposite, and if Fnet=0, we now acceleration must be 0.