Translation:How can I know the mass of this car?
In physics there is a distinction between mass ("massa"?) and weight ("peso"?). In outer space an object still has mass, but not weight (weight is due to the earth´s gravity). Both are measured in kilograms and most people are not aware of the difference (and why should they care). As this is a language course not a science course Duolingo should use ordinary words and avoid issues like this.