Question

A beam $9$m long, $40$cm wide and $20$cm high is made up of iron which weighs $50$kg per cubic metre. The weight of the beam is

• A. $56$kg
• B. $48$kg
• C. $36$kg
• D. $27$kg

Answer 1

The correct option is C $36$kg

Volume of the cubic iron beam = $Length\times Width\times Height=9\times 0.4\times 0.2=0.72m^3$

Density of Iron = $50kg/m^3$

$\therefore$ The weight of the beam = $Volume\times Density=0.72\times 50=36kg$ $\left[C\right]$.