Why aren't forces N and G equal?

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The discussion centers on the confusion regarding why the normal force (FN) and gravitational force (FG) are not equal for a 2kg block on a frictionless plane. The participant notes that while FN is measured at 9.807N and FG at 19.613N, they expected these forces to balance since there is no vertical acceleration. Concerns are raised about the accuracy of the Interactive Physics program, which may be displaying incorrect information. The participant seeks clarification on whether their understanding is flawed or if the program is indeed at fault. The conversation highlights the importance of real-time discussions in online learning environments.
leatherneckpa
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I am struggling with this one. The question is to explain why the gravitational and normal forces are not equal. And I'll be darned if I know why they aren't. Logic tells me they should be equal. The small block has a mass of 2kg. And multiplying that mass times the normal (9.8N) gives me the gravitational (19.6N). Unless the normal is a constant 9.8N per kg for ALL objects?

Forcesscreenshot.jpg
 
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Please describe the problem completely. What does that diagram show?
 
Did you make that diagram, or is it from other source?
 
The diagram is a portion of a screenshot from an exercise in a program called Interactive Physics. The horizontal plane is a frictionless plane. The small block is just a 2kg mass. FN is Normal force and reads 9.807N. FG is Gravitational force and reads 19.613N. FT is the applied force from the green arrow of 8N horizontal.

I'm supposed to explain why FN does not equal FG. But I thought they had to be balanced, hence equal?
 
leatherneckpa said:
I'm supposed to explain why FN does not equal FG. But I thought they had to be balanced, hence equal?
If the vertical acceleration of the block is zero, then the net vertical force must zero. Assuming that's the case here, that diagram looks incorrect.
 
Doc, there is no vertical acceleration. And so I figured I must be screwing something up. According my admittedly limited understanding FN should be equal to FG. If things were as the program is showing me it seems to me the block should be sinking downward (due to FG) in addition to moving to the right from the applied horizontal push.

There have been reports of this program screwing up in our online community. I just wanted to be sure the program was wrong and not me.
 
leatherneckpa said:
I just wanted to be sure the program was wrong and not me.
I don't think it's you. :wink:
 
OK, thanks.

Love this new resource too. Glad you guys are here. That's the only thing I have found so far that I don't like about online college, nobody to discuss things with in real time.

BTW, where's the link for the 20% discount on SciAm? I think I'd like to take advantage of that.
 

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