How Does Newton's Second Law Explain Equilibrium and Changes in Apparent Weight?

[vinny380]

Can anyone please help me with these two problems?? I have been trying to figure them out for a while, but cant...

1. A net force of 125 N acts on an object. Find the single force that will produce equlibrium?
Is the answer a force of -125N acting back on the object?? Seems
to easy =/

2. An elevator is traveling from the lobby to the top of a building. As it slows to a stop on the top floor, what happens to your apparent weight?
The question is kind of confusing - I know that on the way up, your apparent weight will be higher than your normal weight...but when it comes to a stop ... wouldn't it be the same as weight??

 

[Astronuc]

1. It depends on what is meant by equilibirium. If equilibrium infers no acceleration or a balance of forces, then and equal force must oppose the other force, and in this case 125 N requires 125 N in the opposite (-) direction.

As for the second problem, obviously one's weight does not change, but the initially the elevator must accelerate against one's weight to obtain some velocity. So one feels heavier. Then at constant velocity (in the gravitational field) one feels normal.

What happens at the top as one approaches the end of the journey?