Question

PartA Rock has mass per volume about 3 tmes that of water, Estimate the diameter of a 20-ton rock (1 to: 2,000 lb). Suppose that the rock has a spherical shape. which is 1 kg per liter (10 cm3 or 62 lb per cubic Express your answer using one significant figure. foot A24 ft d-

Answer 1

Density of the rock = 3 x 1 kg/liter = 3 kg/liter = 3000 kg/m³

and density = mass / volume

here, mass of the rock = 20 ton = 2000 x 20 = 40000 lb = 18143.7 kg

=> volume of the rock = 18143.7/3000 = 6.048 m³

volume of a sphere is given by:

$V = \frac{4}{3}\pi R^3$

so, $6.048 = \frac{4}{3}\pi R^3$

=> R = 1.1302 m

this is the radius of the rock. Its diameter will be:

D = 2R = 2.2605 m = 7.416 ft or approximately 7 ft [one significant figure]