I'm not really good at physics and if someone can explain me this with easy words, would be great.As you sit on a chair, does the chair an upward force against your butt? how much force does it exert? In what direction?
Quite Simply: Yes, the chair exerts a reactive force. Reactive forces 'react' to other forces being exerted on an object. In this case, gravity. If there was no gravity, there would be no force exerted by the chair. The reactive force the chair exerts is known as a normal force, normal meaning the direction of the force is perpendicular to the surface. With a chair parallel to the ground, yes, the force exerted by the chair would be upward, and equal to your weight.
actually yes and no. the force of the chair is a resistance force. is a resistance force because gravity is pulling the person down however the chair stop him from going all the way down. an example of a such thing is a sheet of paper and a book. hold both the book and the paper and let go of them at the same time. you'll notice that the book would reach the ground first. here the resistant force is the air because the book is heavy air cant stopped it or slow it down. however the paper is much lighter so it can slow it down. an upward force means that it's pushing up instead of just resisting.
