Question

The linear density of a rod of length 9 m is given by ρ(x) = 1 / √x, in grams per centimeter, where x is measured in centimeters from one end of the rod. Find the mass of the rod.


__________ g

Answer 1

9m = 900 cm
M = int_0^900 ( ρ(x) dx) = int_0^900 ( 1 / √x& dx) = 2√900 = 60 g.