Answer to Question #94991 in Mechanics | Relativity for m. Jahanzaib Hassan

Question

a ball made of a long string of thickness about 2mm the radius of the ball is 10cm esimate the length of the string and possible error inyour calculation.

Answer 1

$length\ of\ string\times thicknes=area\ of\ ball$

$l\times0.2\ cm=4\pi r^2=4\times3.14\times10^2=1256$ cm

$l=\frac{1256}{.2}=6280\ cm\\\ \ \ \ =62.8\ m$

Error in calculation will be

$\frac{1}{2}\times10^{-n}=0.05$

$n=1\ here\\\ because\ no.\ of\ digit\ after\ decimal\ is\ one$

error in calculation=$0.05 \ m$