The normal force

[grief]

In which cases is the normal force acting on an object simply mg, and in which cases is it something else? If it's not mg, how can I figure out what it is?

[Leong]

the normal force depends on the situation. but you will always need to use newton's 2nd law.

[grief]

ok, so I don't really understand what the normal force is. By what is it exerted, by the ground? and it's not always upward, correct? it's perpendicular to the object, I think.

[Leong]

you have normal when you have two objects that have contact. the direction is perpendicular to the contact surface. upwards or downwards will depend on which object you are referring.

[grief]

Ok, I got it, thank you.