 Let's explore the idea of balanced and unbalanced forces. To take an example, imagine you have a refrigerator which is being pushed by two people with exactly the same force but in the opposite direction. Let's say the force is five units each, don't worry about the unit of the force, we'll look at the units in a different video. But let's say we are putting five units of force in either direction. The question that I want to try and ask ourselves is does do these forces do anything to a refrigerator? Does it affect the refrigerator? Our answer will be no because you're pushing them in the two opposite direction, it's not going to do anything. If my refrigerator was at rest, to begin with, it's going to stay at rest. Since these two forces are not going to affect the refrigerator, we say these forces are balanced forces. The force on the left-hand side is literally balancing the force on the right-hand side. Another way to think about this is we would say that the total force must be zero. That's why the refrigerator is not getting affected. Yes, we are pushing on it, both the people are pushing on it, but if you push them with the same force in the opposite direction, they don't affect it. They cancel each other out. So the total force must be zero. And the way we write that is we basically say the total force F net, net means total in physics. We just like to write net force. So the net force is zero in this situation. This also means, interestingly, five plus five, when it comes to forces, need not be 10. If they are in the opposite direction, look, they become zero, which means if the forces are in the opposite direction, you subtract them. So whenever the net force is zero, we say they are balanced forces and they do not affect the refrigerator or their objects motion. But now let's consider the two of them are pushing the refrigerator in the same direction. What's going to happen? Well, if there is no friction and no other forces, let's say, you would agree that the refrigerator will start moving, right? But not just that. Imagine the refrigerator was already moving and it was coming towards the left. Now what would these forces do? Ha, now imagine somebody was somebody, somebody had thrown the refrigerator towards them. Now by pushing it against the direction of its motion, it will slow it down and it can make it stop. So see, these forces can start the motion. They can also stop the motion. And as a result, these forces now can affect the motion unlike over here. And so we will now say these are unbalanced forces because there's no force that's balancing it. And because it's unbalanced, it's affecting the motion. And what's the total force now? Well, see if the forces are in the same direction, we add them. So now the total force is 10, but in general, when it comes to unbalanced forces, the total force or the net force will not be zero. So if the net force is zero, it's balanced, doesn't affect the motion. If the net force is not zero, it's unbalanced. It does affect the motion. Now I want to be clear about one thing though, okay? We might think unbalanced forces will always make things move. That's not true. We just saw in this example, unbalanced forces can also make things stop moving. It all depends upon what that refrigerator was doing before we put the unbalanced force. So it's not very straightforward and we'll understand how unbalanced forces act on, you know, objects, how it affects the motion in more detail later on. We call them the Newton's laws, but it's not so straightforward. Don't think unbalanced forces cause motion. Okay. All right. Okay. So now that we understood what balanced unbalanced forces are, let's take a couple of examples. Okay. Consider this situation. We have a car with the forces like this. Can you pause and think about whether the forces are balanced or unbalanced and think about the total force? Is it zero? Not zero? What is it? Can you pause and try? Okay. Let's do this. Well, clearly, the force on the right is not balanced by the force on the left, right? It's 10 units and for the force on the left is only four units. You can see the force on the right wins. Therefore, what is the total force? Well, first of all, therefore it is unbalanced, right? The force towards the right is not balanced by the force towards the left. But what is the net force? Well, again, they're in the opposite direction, so you subtract them. So we do 10 minus four, you get six. So the answer is six. In which direction to the right? Because this is the bigger force. So the net force is to the six units to the right. As a result, what will the car do now? You might say, oh, the car will start moving. But no, remember, that again depends on what the car was initially doing. If the car was at rest to begin with, yes, then the car will start moving towards the right. But what if the car was already moving backwards, right? Then when you put the force, it'll slow it down and might make it stop, like just the refrigerator. So remember, the relationship between net force or unbalanced force and motion is not very straightforward. And we're going to learn about all of those things in future videos. But as of now, just think about balance and unbalanced force. Don't worry too much about the motion part of it. Okay. All right. One last. Consider this. Are the forces balanced or unbalanced? Pause and try. All right. The force towards the left, there are two of them. If they're in the same direction, we add these two forces, so seven plus five is 12. So there's a 12 force towards the left and yay, look at this. You have 12 force towards the right. The two perfectly balance each other out. And so we have balanced forces. What is the net force? That means zero. The total force on this rock is a zero.