Question

A rocket is in the form of a circular cylinder closed at the lower end with a cone of the same radius attached to the top. The cylinder is of radius $2.5m$ and height $21m$ and the cone has the slant height $8m$. Calculate the total surface area and the volume of the rocket.

Answer 1

Total surface area = Area of base of cylinder+ Area of curved surface of cylinder+Area of curved surface of cone

$A=\pi \times r^2+2\pi rh+\pi rl$

h=height of cylindrical part

l=slant height of conical part

r=radius of cylinder=radius of cone

$A=\pi \times {2.5}^2+2\pi \times 2.5\times 21+\pi \times 2.5\times 8$

$A=412.334m^2$

Volume of tent$=\pi r^{2}h+\frac{1}{3}\pi r^{2}h$

$V=\pi \times {2.5}^2\times 21+\frac{1}{3}\pi \times {2.5}^2\times 7.6$

$V=462.076m^3$