If the momentum of a car increases by 8.6 kilogram meters per second squared, in 16 seconds, what is the average force accelerating the car? Okay, so let's do our stock taking. We have that the momentum increases by, that means that how much it is changing with. So it is delta P. The change in momentum is equal to 8.6. Okay, and in 16 seconds, it means the change in time is equal to 16 seconds. Okay, and the next part is asking us to calculate the net force that's causing this change in momentum. What is the net force? Well, let's see which formulas can we use for the net force? Okay, here we see we can use this formula, where the net force is mass times acceleration. We don't have mass or acceleration. So our alternative is for this formula. Okay, and here you can see the net force times the time is equal to the change in momentum. And we have time and we have momentum. The only thing we don't have is the net force in this part of the formula. So that means that I can use that the net force times change in time is equal to the change in momentum. So the net force multiplied by 16 will give me 8.6. And all I need to do now is to divide both sides with the 16, both sides with the 16. And then I get my answer that the net force is equal to 8 divided by 16, sorry 8.6 divided by 16 gives me 0,5375, 0,54. Let's go for 0,54 Newton's, round to two decimal places and let's go into that answer. We've already seen that this is the formula that we are going to use. In that formula we need, we want the net force. We have time 16 seconds and we have the change in momentum. So when we substitute that, we're going to ignore subscripts as always. So force times 16 is equal to 8.6. Preview looks good. So when we solved it, we found that the force is 0.54 Newton's. Preview, that looks good. Now just one more thing that I myself very often forgets and if I do forgive me, but what we do have to remember is that force is a vector. It is applied in a direction. Time can't be applied in a direction. So they're not vectors. But since force is a vector, we need to include it in a direction. And since we don't really know what the direction is, we simply say it's in the direction of motion. In the direction of motion. Since it is positive. If it was negative, we would have said in the opposite direction of motion, if we didn't know what direction with its up or down or whatever. So please remember that. See if you can surpass me in this and remember that better than I do. Cool.