Final answer:
When a junked car is crushed into a compact cube, its mass remains the same, but its volume decreases significantly. The weight of the car would also remain the same.
Step-by-step explanation:
When a junked car is crushed into a compact cube, its mass remains the same. However, its volume decreases significantly since the car is compressed into a smaller shape. The weight of the car would also remain the same as weight depends on the mass and the force of gravity, both of which remain constant.