Question

What will be the thrust exerted by a cylindrical object of the length 49 cm, radius 7cm and density $2.2gc{m}^{-3}$ placed on a table?

(Acceleration due to gravity is $9.8m{s}^{-2})$

Answer 1

Radius of the base $\left(r\right)=7cm$
Length of the cylinder $\left(l\right)=49cm$
$Density\left(d\right)=2.2gc{m}^{-3}$
Acceleration due to gravity $\left(g\right)=10m{s}^{-2}$
To find the thrust exerted, first we have to calculate the mass of the cylinder.
Mass of the cylinder $=V\times d$
$=\pi r^{2}l\times d$
$(\therefore$ volume of the cylinder $=\pi r^{2}l)$
$=\frac{22}{7}\times 7\times 7\times 49\times 2.2=11601.2g$
$=16601.2\times \frac{1}{1000}kg=16.601kg$
$\therefore$ Thrust exerted $=mg$
$=16.601\times 10=166.01N$.