Answer
(a) The object will attract the glass rod.
(b) We can't predict what the object will do with the glass rod.
Work Step by Step
When a plastic rod is rubbed with wool, the plastic rod becomes negatively charged. When a glass rod is rubbed with silk, the glass rod becomes positively charged.
(a) If an object repels the plastic rod, then the object must be negatively charged. Then it will attract the glass rod.
(b) If an object attracts the plastic rod, then the object could be neutral or positively charged, but we don't know which. Then the object would attract the glass rod if the object is neutral, but it would repel the glass rod if the object is positively charged. Therefore, we can't predict what the object will do with the glass rod.
