Balanced and unbalanced forces | Forces and Newton's laws of motion | Physics | Khan Academy

you'll hear the terms balanced forces and unbalanced forces a lot when you're dealing with physics and what i want to do in this video is give you a bunch of scenarios and have you think about whether the forces in these scenarios are balanced or unbalanced so let's start with a scenario where we have the ground and then sitting on the ground we have we have a rock now the force of gravity is going to be pulling the rock downwards toward towards the center of the earth and it's going to be pulling it as essentially the weight of the rock it's going to be pulling it downwards let's say at with a force of five newtons five newtons downwards but then the rock is also being supported by the ground the ground is keeping it from being plummeted downward so the rot so the ground is providing an upwards force or normal force in this situation the ground is providing a normal force i'll do it in the green the ground is providing a normal force in this situation of five newtons so these forces have the same magnitudes but they're going in opposite directions so that is the first scenario now let's so i'll draw the rock again so i'll draw that same rock so now i will i will draw that same rock we'll assume it's the same rock the force of gravity is still downwards five newtons five newtons downwards and there's still a normal force the ground supporting the rock of five newtons upwards 5 5 newtons upwards 5 newtons upwards and now there's some character who's trying to push the rock so we have some character here and he is trying to push the rock and he's applying a force of he's applying a force of two newtons to the right but then there is a force of friction between the rock and the ground that is going to and i'll do friction in orange two newtons to the left