To solve this problem it is necessary to apply the concepts related to the Conservation of Energy, for which it is necessary that any decrease made through the potential energy, is equivalent to the gain given in the kinetic energy or vice versa.
Mathematically this can be expressed as

Since there is no final potential energy (the height is zero), and the initial potential energy is equivalent to the work done we have to






Therefore the non-conservative work was done on the boy is 1.4kJ
The correct answer to this problem is C
Answer:
When the electrical current passes through the conductors, the polarity is changed, and the diaphragm interacts with the permanent magnets, vibrating and creating sound.
Explanation:
Whn u hit the laces with ur foot it doesn’t got str8