Question

a pulley was made from two big equal cylinders stuck at the end of a small cylinder to draw water from well, as shown in figure. find the CSA​

Answer 1

cylinders CSA=2x2πrh=2x2x3.14x10x10.5

= 1318.80 cm2

CSA of small cylinder:

2πrh=2x3.14x2x7=87.92cm2

CSA (total) 1318.80+87.92 = 1406.72cm2. Ans

Answer 2

Given ,

1. Radius of big cylinder = 10.5/2 cm
2. Radius of small cylinder. = 2 cm

To find :

CSA of given figure

solution :

formal to be used :

$CSA \: of \: whole \: fig. \: = 2 CSA \: of \: big \: cylinder + CSA \: of \: small \: cylinder$

$CSA of cylinder = 2\pi \: rh$

$CSA of \: big \: cylinder = 2\pi \: rh = 2 \times 3.14 \times \frac{10.5}{2} \times 20 = 659.4 {cm}^{2}$

$CSA ofsmall \: cylinder = 2\pi \: rh \\ = 2 \times 3.14 \times 2 \times 7 = 86.92 {cm}^{2}$

$CSA of total \: fig. = 2 \times 659.4 + 86.9 = 114603.7 {cm}^{2}$

Hence,

CSA of given figure 114603.7cm^2