Respuesta :

Answer:

4 kg

Explanation:

Answer: The mass is 4kilograms

Explanation:

Kinetic energy = 1/2 X (Mass X Velocity*2)

18 = 0.5 X Mass X 3*2

18 = 0.5 X Mass X 9

18 = 4.5 X Mass

Mass = 18/4.5

Mass = 4kg