LOS ANGELES, California (Reuters) — Tesla Inc on Thursday (November 16) unveiled a prototype electric big-rig truck, throwing itself into a new market even as it struggles to roll out an affordable sedan on which the company’s future depends. Chief Executive Elon Musk unveiled the big rig, dubbed the Tesla Semi, by riding the truck into an airport hangar near Los Angeles in front of an invited crowd of what Tesla said were potential truck […]