# How do I describe me pushing someone when we are both on office chairs?

The situation is, my colleague and I are sitting on wheeled office chairs. He weighs more than me. When I push him, he remains at rest and I move backwards. Is this because he has more inertia than me?

If it was just due to inertia, then if I got off the chair and was just standing on the floor, then I would still move. But as I now have more friction with the floor than him, he now moves.

Would the amount of force I apply effect the outcome? Or is it the length of time of the application of force that matters?

• Do you think that the friction in the wheels of the chairs might affect what is happening? If so, do you think that the friction in the wheels is the same for both chairs? Commented Sep 21, 2017 at 16:03

Yes, the amount of force applied affects the outcome. What's happening is that any force that you apply comes in a force-pair by Newton's third law, so if you push on him with a force $\vec F$ then the force $-\vec F$ is imposed on you to impose a property called "conservation of momentum," which in a very deep sense comes from the fact that the laws of physics are the same if you move one millimeter over from where you presently are. If you perform this experiment in a frictionless setting you will both move inversely proportional to your masses.