Final answer:
The velocity of the body is 20 m/s.
Step-by-step explanation:
To find the velocity of a body given its mass and kinetic energy, we can use the formula for translational kinetic energy: KE = 0.5 * mv^2. In this case, the mass of the body is 0.1 kg (since 100 grams = 0.1 kg) and the kinetic energy is 20 J. Plugging these values into the formula, we have 20 = 0.5 * 0.1 * v^2. Solving for v, we find that the velocity of the body is 20 m/s.