Answer:
11.4 kg
Explanation:
kinetic energy = ½mv²
where v is speed and speed is 4.31 m/s,
½×m×(4.31)² = 106
(1)m×(4.31)² = 106×2
(2)m = (106×2) ÷ (4.31)² = 11.41251393 ≈ 11.4 kg
further details
(1)multiply 2 on both sides if the equation to remove the ½
(2)divide both sides by 4.31² to remove 4.31² from the mass
since all values used in calculation are in SI units (speed is in m/s and mass in formula is in kg), the final answer is already in kilograms.