Now, gravitational force, normal force, what are they? What do they have to do with each other?
Well here it is. Gravitational force is the force pulling something down. Normal force… You know how when there’s something on a table, the thing doesn’t sink into the table, but the table doesn’t launch it either? Normal force does that. Normal force is the force an object exerts to counter the force of another object trying to push through it. It’s usually gravity’s equal and opposite reaction. I’ll show you what I mean.
Let’s show up at a beach in southern India, that’s close enough to sea level and the Equator. Let’s bring a 2500 kilogram elephant with us while we’re at it.
Well here it is. Gravitational force is the force pulling something down. Normal force… You know how when there’s something on a table, the thing doesn’t sink into the table, but the table doesn’t launch it either? Normal force does that. Normal force is the force an object exerts to counter the force of another object trying to push through it. It’s usually gravity’s equal and opposite reaction. I’ll show you what I mean.
Let’s show up at a beach in southern India, that’s close enough to sea level and the Equator. Let’s bring a 2500 kilogram elephant with us while we’re at it.
2500Kg•9.81m/s2
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2500•9.81=24525
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24525N
↓
2500•9.81=24525
↓
24525N
The elephant weighs 24525 Newtons. That being true, it exerts 24525 Newtons of force on the ground just by standing there, and that force acts in a downward direction. The elephant doesn’t sink into the ground, nor does it get launched up into the air, and is pretty happy with that. So, what conclusion can we gather from that? The normal force is equal to the elephant’s weight, but in the opposite direction, pushing up against the elephant’s feet. Yes, gravitational force is 24525N down, so normal force is 24525N up.
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