Find the \"relativistic mass\" of an electron (\"relativisticmass\" = m 0 , rest

Question

Find the "relativistic mass" of an electron ("relativisticmass" = m0, rest mass = m0 = 9.11 x10-31 kg) whose velocity is 0.99c. What happens to the"relativistic mass" as the speed approaches c? How does thissupport the conjecture that objects that have mass can never reachthe speed of light? My work so far: relativistic mass = mr rest mass = m0 = 9.11 x 10-31 kg So, mr = m0      = 9.11 x 10-30 kg So the relativistic mass increases as the speed approachesc. I'm not quite sure how to answer/explain the last question.Any help would be appreciated.

Explanation / Answer

You have a math error since the 0.99 was not squared. mr = mo / [ 1 -(0.99)2]   = 7.09mo    Thus, the mass has increased by afactor of 7 when v = 0.99 c.   When v = 0.999 c,    mr = 22.4 mo When v = 0.9999c,    mr = 70.7 mo When v = 0.99999c,   mr = 223.6 mo When v = 0.999999c,   mr = 707.1 mo When v = 0.9999999c, mr = 2,236 mo When v = 0.99999999c,   mr = 7,071mo When v = 0.999999999c.   mr = 22,361 mo Thus, mass approaches , as v approaches c.  The physical reason mass can never reach the speed of light is thatif it did, the mass would be infinitely large, and according to F =ma, the force needed to accelerate it would also be infinitelylarge. Since there is no such thing as an infinitely largeforce, then the mass cannot be infinite, and thus the speed of themass can never reach the speed of light. Thus, mass approaches , as v approaches c.  The physical reason mass can never reach the speed of light is thatif it did, the mass would be infinitely large, and according to F =ma, the force needed to accelerate it would also be infinitelylarge. Since there is no such thing as an infinitely largeforce, then the mass cannot be infinite, and thus the speed of themass can never reach the speed of light.

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