Forces appear when two objects interact with each other. Each force is represented by an arrow to show its direction. Force could be a push or a pull
The engine is providing a force to accelerate it forwards, but there is another force acting, which tends to slow down the car. This is air resistance, a form of friction caused when an object moves through the air. (Friction is also called drag, especially for motion through liquids.) The air drags on the object, producing a force that acts in the opposite direction to the object’s motion.
A driver who needs to stop quickly will apply the brakes to take advantage of solid friction
The kinetic energy of the car transfers into thermal energy, raising the temperature of the brakes. You can demonstrate this for yourself by rubbing your hands together.
Compare standing on concrete with standing on ice. There is much more solid friction on concrete and you do not have to think about keeping your balance. The solid friction between the sole of your shoes and concrete impedes motion (so reduces the possibility of slipping) and, because there is no motion of one surface against another, there is no increase in thermal energy.
If you are running quickly on concrete and fall over you may notice that the graze on your knee feels hot. This is because your kinetic energy transfers into thermal energy due to the solid friction between your skin and concrete.