Question

observe a heavy vehicle and a light vehicle. You will notice that the heavy vehicle has wider tyres and the light one has narrow tires. why​

Answer 1

It is because the heavy vehicle has more weight and cannot use the narrow tires. on the other hand the light vehicle cannot use wider tyres as it will not be managable

Answer 2

The heavier vehicle’s tyres need to be able to carry the weight of the vehicle. By using wider tyres, the weight of the vehicle is actually being distributed evenly over a larger area (Pressure=Force/Area). This reduces the pressure applied by the vehicle and force required to move it becomes lesser.
The lighter vehicle uses narrower tyres as it is lighter and does not apply much pressure on the ground. Hence requires lesser force to push and the narrow tyres have the perfect area for equal distribution of weight for a light car.

I know it is quite lengthy but hope it helps