A. Frictional heating is the work done to overcome friction and convert mechanical energy into internal energy, so A is correct;
B. Frictional electrification is the transfer of electrons, which can convert mechanical energy into internal energy. electrical energy, therefore B False;
C. The electric motor that drives the water pump to send water to a high place converts electrical energy into mechanical energy, so C is correct;
D. When charging the battery, electrical energy is converted into chemical energy, so D is false.
So choose AC.
The electric motor drives the water pump to send the water to high places for energy conversion
(1) The dam is built to increase the level of water upstream. remains unchanged, height increases and gravity Potential energy increases as water falls, gravitational potential energy is converties in kinetic energy and the kinetic energy increases, thus pushing the generator to produce electricity.
(2) The generator works based on the principle of electromagnetic induction. It consumes mechanical energy and obtains electrical energy. It is a device that converts mechanical energy into electrical energy.
So the answer is: movement; electromagnetic induction.
A. When sawing wood with a saw blade, the process of heating the saw blade - mechanical energy is converted into internal energy, so A is wrong
B. The electric motor drives; the water pump to send water to a high place - Electrical energy is converted to mechanical energy, so B is correct;
C. Plants absorb sunlight for photosynthesis - l Light energy is converted to chemical energy, so C is correct;
D. Burning with natural gas The heat generated whene boiling of water - chemical energy is converted to internal energy, so D is correct;
Therefore, choose A.