Respuesta :
energy is neither created nor destroyed
E in = E out
750 J in so 750 J out
E in = E out
750 J in so 750 J out
Since the energy is conserved, it's not lost, it's conserved. so the 750J of chem should go into cutting the grass, making a noise whilst doing so, and getting warm whilst doing so. How much into which is presumably decided by the (efficient ?) design of the machine.