Q14 of 146 Page 145

How fast should a man of 50 kg run so that his kinetic energy will be 625 J?

m = mass;

v = velocity/speed;


K.E. = kinetic energy


Given that m = 50kg and KE = 625


1/2(mv2) = KE


1/2(50v2) = 625


v2 =625 × 50 × 2


v = √62500


= 250m/s


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