5. Classify: Astronomers classify the eight planets in our solar system into two groups: terrestrial planets and gas giants. Terrestrial planets have rocky surfaces, while gas giants
are composed mainly of gas. Based on your data, classify each planet as a terrestrial planet
or a gas giant. (Hint: Look at the density of each planet.)

How much force must a locomotive exert on a 12840-kg boxcar to make it accelerate forward at 0.490 m/s2?

Which statement best describes how private industry decides where to spend the money on research and development

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.