define hooke's law
giveExamples of hooke's law
Answers
HOOKE'S LAW AND ASSUMPTIONS - LAW
According to Hooke's law strain produced in any body, is directly proportional to stress applied within the elastic limit. Moreover, For a spring, F needed to extend or compress by some distance X is proportional to that distance. That is, F=−kX, where k is a constant factor characteristic of the spring: its stiffness, and X is small compared to the total possible deformation of the spring.
Assumption:
1. This law is true only for linear elastic bodies.
ELONGATION OF WIRES WHERE STRESS VARIES ALONG LENGTH OF WIRE - EXAMPLE
Example: A solid sphere hung at the lower end of a wire is suspended from a fixed point so as to give an elongation of 0.4 mm. When the first solid sphere is replaced by another one made of same material but twice the radius, what is the new elongation?
Solution:
as radius is doubled volume becomes 8 times and, hence, the weight of sphere. The force becomes 8 times
FαΔL
∴ΔL also becomes 8 times
ΔL
′
=8×0.4mm
=3.2mm