A hair dryer's electric motor is supplied with 900 kJ of electrical energy but only has an output of 700 kl of rotational energy.
a)
Explain why the input energy is not equal to the output energy of the electric motor.

Trumpeter a holds a b-flat note on the trumpet for a long time. person c is running towards the trumpeter at a constant velocity. person b is running away from the trumpeter at the same rate. person d is standing still the whole time. which person hears a frequency that is lower than the b-flat?

Which graph best represents the relationship between the electric current and the rate at which a magnet is turning inside an electric generator?

What happens to atoms and chemical bonds during a reaction?