Our teacher made an unconvincing argument based on this example:
If a horizontal force of 15 N were a applied to a 2 kg block, and the work done was 20 J, what distance did the object move?
2. The attempt at a solution
Using W=F*d the teacher solved this: 20 J=15 N*x -> x=4/3 m.
This implied that if I applied 15 N to an object of any mass and did 20 J of work, the distance I could move the object is always the same. There seems to be something fundamentally wrong with this statement. But I'm not seeing what it is, I know it's there - I'm think that somehow I need to do something with the weight of the object. I mean if it were to be realistic I would have to calculate friction and gravity too...
Can somebody please tell me what I missed out?