The answer is 6 Joules. The kinetic energy (KE) of an object is the product of half of the mass (m) of the object and the square of its velocity (v²): KE = 1/2m*v². We know that m = 0.75 kg and that v = 4 m/s. Therefore, KE = 1/2 * 0.75 kg * (4 m/s)² = 1/2 * 0.75 kg * 16 m²/s² = 6 kg*m²/s² = 6 J.