Chapter 12.9, Problem 21HP

To determine

To find : Which ice cube melt faster

Answer to Problem 21HP

Half cylinder

Explanation of Solution

Given information :

The given information is,

  

Length ( $l$ ) = $3$ cm, Breadth ( $b$ ) = $2.5$ cm and Height = $3$ cm of cuboid.

Radius = $1.7$ cm of cylinder and Height ( $h_1$ ) = $5$ cm.

Formula Used:

Surface Area of cuboid = $2(lb+bh+hl)$

Surface Area of half cylinder = $\pi rh+bh+\pi r^2$

Calculation :

Surface Area of given cuboid $=2(7.5+7.5+9)=48{\text{ cm}}^{\text{2}}$

Surface Area of given half cylinder

  $\begin{array}{l}$ =3.14\times 1.7\times 5+3.4\times 5+3.14{(1.7)}^2$=26.69+17+9.07\\ =52.76{\text{ cm}}^{\text{2}}\end{array}$

So, half cylinder will take more time to melt As it has more surface area.