It's tough being a parent. Sometimes I try to help my kids with their physics homework because I like to pretend that I'm sort of OK with physics. Recently, my daughter wanted me to check her answer for this question.
Oh boy. I'm not sure what answer to give. OK, I think I know the answer and I also think I know the answer that the teacher wants (and these two answers might not be the same). Really, it's not the best question. It's sort of ambiguous. Here are the thoughts that go through my head in my attempt at helping.
There are actually two common definitions of "weigh." Let me start with the most physics-like (and more technically correct) version.
Weight: Weight is the magnitude of the gravitational force between an object and a planet (typically, the planet is the Earth). On the surface of the Earth, the weight of an object is approximately the product of object mass (m) and gravitational field (g) where g is 9.8 Newtons per kilogram.
I tried to make that a formal definition—just to be complete. In short, weight is the gravitational force. Here is the other definition that could be used for weight.