Students repeat the experiment but replace block X and block Y with block W and block Z , as shown in Figure 3. Block W and block Z have identical mass M . When the experiment is conducted, the students observe that the blocks do not stick together, as shown in Figure 4. The students predict the speed of block Z after the collision by assuming that the collision is perfectly elastic. They then collect data about the actual speeds of both blocks immediately after the collision, as shown in the table.

Why does the predicted speed of block Z after the collision not agree with the actual speed of block Z after the collision?

The block Z would be seen in figure 10 when 4 strident turn around

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -