So, I was reading the quite funny
Engineering Trivia page at the RF Cafe. At this writing, one item there reads, "If a passenger car with a stationary weight of 1000 kg (220 lbs) is accelerated from rest to 60 km per hour (40 mph), it gains something like the weight of a pinhead in the process. If the car could be made to travel at 100 times the velocity of sound (100 X 1200 km per hour) it would become about 100 kg heavier, and at 250,000 km per hour its weigh would be doubled. Traveling at 0.999% of the velocity of light, the car would weigh 2,000 times its stationary weight, and would plough deep furrows in the surface of the road."
And I immediately wrote to the owner of the RF Cafe, pointing out that this is totally wrong. In particular, at 250,000 km/hr (69 km/sec), the car's mass would actually increase by only a fraction of 1%, not double. The equation for mass increase with velocity is:
Where "C" is the speed of light in a vacuum, approximately 300,000 km/sec; V is the velocity of the mass, M1 is its rest mass, and M2 its relativistically adjusted mass.
So, in a sort of pinnacle of the nitpicking arts ... I just nitpicked relativistic calculations.
OK, clearly the original writer meant to say "250,000 km/SECOND", not hour, but that's why it's nitpicking.
Where "C" is the speed of light in a vacuum, approximately 300,000 km/sec; V is the velocity of the mass, M1 is its rest mass, and M2 its relativistically adjusted mass.
