Jim Cramer answers viewers' Twitter questions from the floor of the New York Stock Exchange. This week, Cramer explains why he considers SolarCity and Amazon examples of cold stocks that are set to go higher. He says although it's hard to come up with a valuation for these stocks and others like Tesla and GoPro, he understands that people want to play them and they're going to get hotter. Cramer also weighs in on Ford, explaining why he's a believer and investors don't need to sell the stock. Plus, he reveals how to play the refiners, including his favorite, HollyFrontier Corporation. Tweet your questions for Jim @jimcramer using #CramerQ.