Now, we know some of you might be wondering if we’re referring to the same pedal in the middle that you jam your foot on to when the car needs stopping. The answer is yes, that’s exactly what we are taking about – brakes. So, how then are brakes energy conversion devices? Read on to find out.
Functionally, brakes are supposed to arrest the rate of motion in a moving vehicle or in other words, produce deceleration necessary to slow down your car or halt it altogether. The way they go about achieving that goal is by converting one form of energy into another.
A moving vehicle has kinetic energy, and the faster its moving the more kinetic energy being generated as a result. Therefore, to slow the car, a braking system simply absorbs portions of that kinetic energy. But since the laws of physics require that energy be transformed into some form, the friction basically converts kinetic energy into thermal energy or heat.
So, when you press the brake pedal, what it really does is trigger a chain of processes that ultimately lead the brake pads to press against the disc rotor that’s attached to the wheels of your car. This creates friction between the turning wheels and the disc rotor; friction causes heat which eats away from all that kinetic energy thereby slowing the car down.
Of course, the actual design, form and specific functions of the organs that make up the breaking system can be different based on the technology employed. The end result however is always the same – reducing kinetic energy in a vehicle by transforming it into some other form of energy when the brakes are applied.
For instance, older cars (and some heavier vehicles) have ‘brake drums’ instead of disc rotors but there too, the principle relies on creating friction to dissipate all that motion-based energy into the atmosphere by transforming it into heat.
Similarly, electric cars, or electric trains might seem to employ starkly different braking system. But, there too the kinetic energy is being translated into either electric energy in case of trains or chemical energy that gets refed into the batteries powering an electric car. Thus these type of breaking systems are termed ‘regenerative’.