. Now, consider the object be exaggerated by a multiplier factor = x so that it has a new mass, , and the surface upon which the force is acting has a new surface area, . The new force due to acceleration and the resulting thrust pressure, Thus, just scaling up the size of an object, keeping the same material of construction (density), and same acceleration, would increase the thrust by the same scaling factor. This would indicate that the object would have less ability to resist stress and would be more prone to collapse while accelerating. This is why large vehicles perform poorly in crash tests and why there are theorized limits as to how high buildings can be built. Similarly, the larger an object is, the less other objects would resist its motion, causing its deceleration. Engineering examples Steam engine: James Watt, working as an instrument maker for the University of Glasgow, was given a scale model Newcomen steam engine to put in working order. Watt recognized the problem as being related to the square–cube law, in that the surface to volume ratio of the model's cylinder was greater than that of the much larger commercial engines, leading to excessive heat loss. Experiments with this model led to Watt's famous improvements to the steam engine. Airbus A380: the lift and control surfaces (wings, rudders and elevators) are relatively big compared to the fuselage of the airplane. For example, taking a Boeing 737 and merely magnifying its dimensions to the size of an A380 would result in wings that are too small for the aircraft weight, because of the square–cube rule. Expander cycle rocket engines suffer from the square–cube law. Their size, and therefore thrust, is limited by heat transfer efficiency due to the surface area of the nozzle increasing slower than the volume of fuel flowing through the nozzle. A clipper needs relatively more sail surface than a sloop to reach the same speed, meaning there is a higher sail-surface-to-sail-surface ratio between these craft than there is a weight-to-weight ratio. Aerostats generally benefit from the square–cube law. As the radius of a balloon is increased, the cost in surface area increases quadratically , but the lift generated from volume increases cubically . Structural engineering: Materials that work at small scales may not work at larger scales. For example, the compressive stress at the bottom of small free-standing column