You can't get something from nothing is practically stating the law. The law means states that energy can't be created or destroyed, in other words, it's constant. So in saying so, you truly can't get something from nothing
You're not going to believe this coincidence:. The "tangential" speed is the speed in the direction of the "tangent" to the circle. That's straight ahead, in the direction the car is moving. Since the car is driving in a circle, the tangential direction keeps changing.
