Hooke's law

Hooke’s law of elasticity is used to explain, that how the material body is deformed by stress. Just imagine the weight suspended on the spring. The spring will lengthen according to the Hooke’s law. The materials for which Hooke’s law is a useful approximation are known as linear-elastic or “hookean” materials. The material such as rubber, for which the Hooke’s law is never valid, is known as “Non- Hookean”. The stiffness of the rubber is not only for stress dependent, but is very sensitive to temperature and loading rate.

The extension produced is proportional to the load, for the systems that obey Hooke’s law.

F=-kx

Where, x is the distance the spring is elongated by, F is the restoring force exerted by the spring, and K is the spring constant or the force constant of the spring.

Hooke’s law mathematically comes from the fact that in the most isolated state (solid state) atoms are in the state of stable equilibrium.

Robert Hooke’s law

The Hooke’s law is named after the 17^th century physicist Robert Hooke. Hooke’s law says that the amount by which spring extends is proportional to the force which is acting upon it.

Elasticity

The materials that obey Hooke’s law are known as elastic.  As well stretching, elastic materials will return to their original shape, when the force acting on them is removed. According to Hooke’s law, an elastic material will requires the same amount of force to stretch it by some length. This necessary force depends on the material stiffness. The flexible material requires only less force, while the stiff material needs a large force to extend. The materials that is stretched is said to be under strain. Strain is defined as the percentage increase in length due to stretching. The force that is applied per unit area is also known as stress.

Longitude

Hooke's law is also used in navigation. In the 17^th and 18^th century determining the longitude had put the sailor lives at risk. Clock technology was not advanced during the 18^th century; The British watch maker by name John Harrison came up with the solution to problem by using Hooke’s law. He discovered new type of clock, instead of pendulum, that relied on springs. That was impractical on most voyages, due to the stretchiness of these springs changed with the temperature. Therefore he incorporated a bimetallic strip made from two different metals bonded together into his clock. This incorporation of the strip into the clock mechanism compensated for the temperature change.

Questions:

• What is Hooke's law?
• Is Hooke’s law used in navigation?