To work out the kinetic energy of an object, you use the formula:
E = 0.5 x (mass) x (velocity)^2
One important thing, though. The units MUST be consistent. Mass needs to be in kilograms, and velocity in metres per second.
To convert the mass form grams to kilograms, we need to divide it by 1000, getting 0.0103 kg. Since the velocity is already in the units we need, we can just plug the numbers into the equation to get:
E = 0.5 x (0.0103 kg) x (48.0)^2 = 11.8656 J = 11.9 J, to 3 significant figures
Hope I helped! xx
