# Physics

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You drag a heavy box along a rough horixontal floor by a horizontal rope. Identify the reaction force to each ofthe follwing forces: A) the pull of the tope on the box. B) the friction force on the box C) the normal force on the box, and D) the weight of the box.

• Physics -

B is the reaction of A and vice versa.
D is the reaction of C and vice versa.

• Physics -

what does it mean in the question identify the reaction force is there a certain name???

• Physics -

Newton's third law says that for every action there is a reaction.

So when you pull the box resting on a rough surface, there is a resistance due to the friction between the box and the surface. This resistance is the reaction to the pulling force, the force that balances the applied force.

The same for the weight of the box, which acts downwards. Since it is in equilibrium, i.e. no motion in the vertial direction, there has to be a reaction, which is the reaction from the surface, a force which acts upwards to balance out the weight of the box.

These four forces form two couples. The two forces in each couple act as the reaction of each other.

If you want some further reading, try googling "Newton's third law", or perhaps:
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/CLASS/newtlaws/u2l4a.html

• Physics -

"B is the reaction of A and vice versa. "
is meant to be:
the friction force on the box is the reaction of the pull of the tope on the box and vice versa.