reduce the mass of the box increase the mass of the box make the surfaces of the box smooth make the surface of the floor smooth
I gave my students this multiple choice question: A force of 5 N is required to increase the speed of a box from a rate of 1.0 m/s to 3.0 m/s within 5 s along a level surface. What change would most likely require additional force to produce the same results?

Only one answer is correct among these 4 choices:
- reduce the mass of the box
- increase the mass of the box
- make the surfaces of the box smooth
- make the surface of the floor smooth

Could you tell me which one is correct?

increase the mass of the box