Question

A cylindrical road roller made of iron is 1 m long. Its internal diameter is 54 cm and the thickness of the iron sheet used in making the roller is 9 cm. find the mass of the roller, if 1 cm³ of iron has 7.8 gm mass (use π = 3.14)

Answer 1

Given that, 

internal radius of cylinder road roller (r1) = \(\frac{54}2\) = 27 cm

Thickness of road roller (t) = 9 cm 

Radius of cylinder road roller be R 

t = R – r 

t = R - 27 

R = 9 + 27 = 36 cm 

Given height of cylindrical road roller (h) = 1 m 

h = 100 cm 

Volume of iron=πh(R² - r²) 

= π(36² - 27²) × 100 

= 1780.38 cm 

Mass of 1 cm of iron = 7.8 gm 

Mass of 1780.38 cm of iron = 1780.38 × 7.8 

= 1388696.4 gm 

∴ Mass of roller (m) = 1388.7 kg