Am elastic material has a length of 36cm when a load of 40N is hung on it and a length of 45cm when a load of 60N is hung on it. The original length of the ...

Am elastic material has a length of 36cm when a load of 40N is hung on it and a length of 45cm when a load of 60N is hung on it. The original length of the string is

Answer Details

For Hooke's law F = Ke

$⟹F/e=Kf1/e1=f2/e2\text{Let the original length}=t_0\text{therefore}e1=(36-t_0)cm;e2=(46-t_0)cm\text{if f1}=40N\text{f2}=60N\text{Then}\frac{40}{36-t_0}=\frac{60}{45-t_0}⟹40(45-t_0)=60(36-t_0)\text{therefore}1800-40t_{0}2160-60t_{0}60t_0-40t_0=2160-180020t_0=360t_0=18cm$