Teacher:Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
Teacher: Now, understand the problem? Solve this instance: Experiments have shown that acceleration is exactly inversely proportional to mass, just as it is exactly linearly proportional to the net external force.
Student:
Experiments have shown that acceleration is exactly inversely proportional to mass, just as it is exactly linearly proportional to what?