Final answer:
If the net work of an object is negative, its kinetic energy will be decreased.
Step-by-step explanation:
The kinetic energy of an object will be decreased if the net work done on it is negative. According to the work-energy theorem, the net work done on an object is equal to the change in its kinetic energy. If the net work is negative, it means that the object is losing kinetic energy. This could happen, for example, if a force acts opposite to the direction of motion, slowing down the object.