Final answer:
The mass of the object is 1,250 kg.
Step-by-step explanation:
The formula to calculate kinetic energy is KE = 1/2mv². We are given that the object has a kinetic energy of 90,000 J and is moving at a velocity of 12 m/s. We can rearrange the formula to solve for mass:
90,000 J = 1/2 * m * (12 m/s)²
Plugging in the values:
90,000 J = 1/2 * m * 144 m²/s²
Dividing both sides by 72:
m = 90,000 J / 72 m²/s² = 1,250 kg
Therefore, the mass of the object is 1,250 kg.