Final answer:
The first step is to loosen the lug nuts to ensure the tire is secure and the force applied is distributed evenly.
Step-by-step explanation:
The first step when changing the tires of a car is to loosen the lug nuts. This is done using a lug wrench or a tire iron. By loosening the lug nuts first, we can ensure that the tire is secure and won't rotate while we apply torque to remove the lug nuts.
From the perspective of torque, loosening the lug nuts first ensures that the force applied to remove them is distributed evenly across all the lug nuts. If we were to remove the lug nuts in any other order, the force applied to remove them would be uneven and could lead to instability or damage to the tire and rim.