Newtons Law of motion question?

Question

When you stand behind a chair and push it over what law is that considreded and how come you haven't fallen over with the chair ?

Answer 1

Good question, you are beginning to think like a physicist...always wondering why something happens the way it does.

The chair is pushed over because there is a net force f > 0 on the back of the chair.  Depending on the shape and density of the chair, that net force is translated through the center of the chair's mass (CM) where F = kf meaning the force at the center of mass is some proportion of the push force f you gave on the back of the chair  

Thus, from Newt's law 2, we have kf = F = CMa > 0; so that the center of mass for the chair is accelerated at a rate of a.> 0.   As the CM moves, the feet of the chair do not because of friction.  So the chair tips as it rotates around the stationary front feet.  When the CM reaches a point just beyond the point where the front feet are, gravity takes over and adds its force in keeping the chair tipping over until its front hits the floor.

Now you, being the smart person you are, let go of the chair as soon as gravity takes over; so it doesn't pull you along with the chair.  And to a point, the reason you don't fall over backward, the other way from the chair, when you push the chair is because friction allows you to counteract that equal but opposite force (Newt's law 3) you applied to the chair.  Thus the net force acting on you is zero; so there is no backward acceleration on your part.

Answer 2

Your question is not that clear I'm afraid. Still I'll try to explain the situation.

When you're pushing a chair from behind, Newton's third law of motion is considered i.e. every action has an equal and opposite reaction. Now the reason that you didn't fall over along with the chair is that you are delivering a greater force than the chair can withstand with its static stabilizing force. Had the reaction of the chair been more than what you are delivering, you would be seen in the floor, that's for sure. But it's never going to happen because being a static body, it will never give greater reaction than the one applied.

For instance, just imagine you are pushing a forward moving truck towards the backward direction. You will not withstand in front of the truck's momentum and action on you and rather it will keep on moving at the same direction it was, even taking you with.

I hope you have your answer.

Answer 3

It`s the "law of self-defence". You stagger into the house, knock over a chair, but you struggle to maintain your balance because you know you woke up your wife, and she`s gonna come out and beat the c**p outta ya for coming home drunk.   lol

Answer 4

NEWTON'S FIRST LAW OF MOTION

you don't fall over with the chair cuz you are not pushing the chair the whole time it is falling, so you wouldn't fall.