Tesla, Inc. and SpaceX founder Elon Musk, who last month said he had received "verbal government approval" to install a Hyperloop transit system that would run through Philadelphia, demonstrated just how incredibly fast the technology could be this week. Elon Musk shared footage on social media Monday of a test pod accelerating to 201 mph in a few seconds. Musk said on Twitter that the video shows the winning design in action at the SpaceX Hyperloop Pod competition at the company's headquarters in Hawthorne, California, over the weekend. He clarified that a passenger version of the transit system won't have the light strobe effect seen in the video – that was just for testing. He also said acceleration wouldn't be uncomfortable. On Sunday, Musk said it could be possible for a test pod to reach supersonic speeds in SpaceX's test tube, which is eight-tenths of a mile long. Might be possible to go supersonic in our test Hyperloop tube, even though it's only 0.8 miles long. Very high accel/decel needed …