O potássio-40 e um dos principais isótopos radioactivas do corpo humano e seu decaimento pôde formar cálcio-40 com a emissão de energia e de partículas radioactivas. No decaimento de k⁴º, produzido Ca⁴º, a particula emitida denomina-se: (dados: número atómico k = 19 e Ca = 20)?

Can someone explain to me how to do this problem ?

When the displacement of a mass on a spring is 12a the half of the amplitude, what fraction of the mechanical energy is kinetic energy? at what displacement, as a fraction of a, is the mechanical energy half kinetic and half potential?

An insulated thermos contains 148 g of water at 72.7 ˚c. you put in a 11.7 g ice cube at 0.00 ˚c to form a system of ice + original water. the specific heat of liquid water is 4190 j/kg•k; and the heat of fusion of water is 333 kj/kg. what is the net entropy change of the system from then until the system reaches the final (equilibrium) temperature?