@thephysicslabs on Instagram: "A car starts with a key using mechanical, electrical, and security systems working together. 🔑🚗 When you insert the key and turn it, the first thing that happens is mechanical—the key shape matches the lock cylinder, allowing it to rotate. As you turn further, electrical contacts inside the ignition switch close, sending power from the battery to the car’s systems. The dashboard lights up and the fuel pump primes. In modern cars, the key also contains a transpond