DC electricity is the force here.
The battery help to get something which is electric to get the power.
You should definitely use a power saw with a guide to saw a straight line. Straight lines can be very difficult with a regular saw and will be much easier for you with a guide.
Most Power wheelchairs use battery power not servo motors. These batteries are provided by many companies and are available online or in stores.
no, but you do need a power source, such as a cell or a power pack if you do not want to use a battery.
power cord
lots
You would use a drill, a sabre saw and possibly a reciprocating saw.
You will need to use the power cord and/or the battery in order to turn the laptop on.
use your pencilcase for this one
Yes, the cassette is inserted into your car stereo which uses power from the battery.
When the phone is turned off, the battery provides a trickle of power to maintain the memory in the phone.
No, In a hydroelectric system force of water rotates a dynamo that generates power. The power must be used or stored in a battery. If the battery is dead you cannot store power.