KE = 1/2 mv²
v = 10 km/h = 2.78 m/s
v = 20 km/h = 5.56 m/s
10 = 1/2 m . 2.78²
m = 2.59 kg
KE = 1/2 x 2.59 x 5.56²
KE = 40.03 J
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