Question about action and reaction force?

Question

Suppose there is an object on top of a smooth surface (frictional force=0). If we give the object a horizontal push, it would normally move forward. But according to Newton's Law on acton and reaction force, when I give the object a push, a force with the same magnitude but opposite direction will exert back on me, and hence the object stands motionless. Is this correct? If not, why?

Answer 1

Not Quite.

It is true that when you push on the object there will be an equal and opposite “reaction” force (Newton’s 3rd law). However, the force is not acting on the same body and thus will not cancel out the force acting on the object.

When you push on the object, you are exerting a force on that object. Newton’s 3rd law states that the object will push back on you with just as much force as you applied to it. So YOU are being pushed the other way, not the block.
The block will accelerate one direction and you will accelerate the opposite direction.

In this manner, momentum is conserved (which satisfies another physical law).
The net acceleration of all masses involved (you plus the object) is zero because there is no net force acting on the entire system even though component of the system may be accelerating internally.

Answer 2

It is not correct. The object will not remain motionless.

One way to look at Newton's 3rd law is to reverse the subject and object of the sentence so there are two forces acting in opposite directions on different objects.

1) Your push on the object. It will make the object move forward.

2) The object's push on you. It will make you move backwards.

Notice that the 2nd force is not a force acting on the object, just you.

Answer 3

Now, assuming you using your hand to push the block. According to Newton's third law, Every action have a reaction. Read it again!!!! Every ACTION have a reaction. What is doing the action here? is it the block? No!! It your hand. The reaction is on your hand. Not the block. When you push/hit the block, your hand will feel hurt. Why? Coz the reaction is acting on your hand the moment your hand do the action.

Newton's Third Law: every action have a reaction with same magnitude but opposite direction. You have to read this over and over again man. Only an action will have a reaction and action is always opposite direction, same magnitude with reaction.

Answer 4

This is a hard concept that we just recently learned about. You need to look at the whole system, not just you and the object. There's more than one action-reaction pair when you put on the object. There's you pushing on the object and the object pushing pack on you, then there's you pushing on the earth in one direction and the earth pushing back on you, the object pushing against the earth and the earth pushing back on it. Because of the huge difference in yours and the earth's masses, you are able to move forward based on the push. Its hard to explain with just words, but if you wanted a diagram, i could probably draw one up if you wanted it. Just let me know.

Answer 5

Pushing on the little frictionless object will cause you to rock away from it, however slightly or mightily that might be. If you impart momentum to the block, an equal amount momentum in the opposite direction will be imparted to you. If you push a grain of sand and give it some velocity, some velocity in the opposite direction will be imparted to you. It will just be to little to notice. If you push on a frictionless freight train on a frictionless track, you will impart a very small velocity to it, but a much greater velocity, in the opposite direction, will be imparted upon you.

Answer 6

For every action there is an equal and opposite reaction means...
the the action will cause an effect on the object ... not you.

Only a dummy would think that.

Goodnight;
Jonnie

Answer 7

This stress is termed the 'known" or "known reaction stress. that is the stress of the table pushing up on the e book. The forces must be balanced if the e book is to stay nonetheless. It the load is larger than the conventional, obviously the table breaks. If the conventional were more beneficial than the load, the e book would glide away i wager haha.

Answer 8

action and reaction act on different bodies. one travels on one direction, other tends to travel on other direction. it desnot apply on same body. remember recoiling of gun's barrel as a bullet is fired. action on bullet sends it forward, its reacion on gun makes gun recoil backwards. if you sit on a wheeled chair and push a table, the table moves forward and you go backward. that is action reaction pair. just remember they apply on different bodies and hence produce different results on those bodies.