*physical science not physics* *40 pts*
why do scientists build models?
a. to make generalizations about natural phenomena.
b. the observed behavior may represent the universe as a whole
c. the universe is big and complex so it may be to create a smaller physical system to study
d. all of the above

The electric potential a distance r from a small charge is proportional to what power of the distance from the charge? a. r^-1 b. r c. r^-2 d. r^2

A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.

Is the vertical component of velocity ever zero?