1. a) 40 J  -  b) 32 J   -   c) 8 J 

 2. The energy transformed by the computer ...

• becomes difficult to use for other energy transformations

• ends up very spread out

• ends up making the surroundings a little warmer

 3.      

Devices	Input energy	Useful energy	Waste energy
TV	Electrical	Light - Sound	Heat
Car engine	Chemical	Kinetic - Light	Sound - Heat
Gas cooker	Chemical	Heat - Light	Sound
Washing machine	Electrical	Kinetic - Light	Sound - Heat