in un negozio di arredamento, un addetto preleva da uno scaffale alto 1,95m un pacco di coperte e lo deposita a terra, spostandolo a velocita costante e compiendo un lavoro di -197j. Qual'è la massa del pacco? Il secondo addetto compie la stessa operazione, ma durante la discesa il pacco ha un'accelerazione verso il basso di 0,20m/s/2. Quanto lavoro compie il secondo addetto?(non considerare le fasi iniziali e finali del moto del pacco)

Why do scientists believe that light is made of streams of particles? scientists believe that light is made of streams of particles because only the presence of photons can explain phenomena observed during experiments on the photoelectric effect. these observations include only some frequencies of light causing the ejection of electrons, no time gap existing between light striking a metal and electrons being ejected, and intensity having no effect on the kinetic energy of the ejected electrons.

What component of earth’s atmosphere exists entirely as a result of photosynthesis?

Materials will have different energies associated with the electrons inside them. this is related to how strongly bound they are by their work function. if we sandwich a material with a very low energy between two materials with a high energy, we create a trap for an electron. if this trap is very narrow in one direction in comparison to the others, this is approximately a 1-dimensional box that confines the electron. what is the lowest energy of an electron in the box if the thinnest direction across the materials is 4.81 nm?