What's the effect on mass at 1/5th light speed? Ah okay, google says only +2% > A particle moving at one-fifth the speed of light (60,000 km/sec or 37,000 mi/

What's the effect on mass at 1/5th light speed? Ah okay, google says only +2% > A particle moving at one-fifth the speed of light (60,000 km/sec or 37,000 mi/sec) has a mass only 2% greater than its rest mass. When a particle's speed approaches the speed of light, however, the mass increase (called the relativistic mass increase) is significant.