Rachel,an engineering student,was asked to make a model shaped like a cylinder with two cones attached at its two ends by using a thin aluminium sheet. The diameter of the model is $3\, cm$ and its total length is $12\, cm$. If each cone has a height of $2\, cm$,find the volume of air contained in the model that Rachel made. (Assume the outer and inner dimensions of the model to be nearly the same.) Unless stated otherwise,take $\pi = \frac{22}{7}$. (in $cm^3$)

$A$ wooden article was made by scooping out a hemisphere from each end of a solid cylinder,as shown in the figure. If the height of the cylinder is $10 \, cm$ and its base radius is $3.5 \, cm$,find the total surface area of the article (in $cm^2$).

$2$ cubes each of volume $64 \, cm^3$ are joined end to end. Find the surface area of the resulting cuboid in $cm^2$.

$A$ container shaped like a right circular cylinder having diameter $12 \, cm$ and height $15 \, cm$ is full of ice cream. The ice cream is to be filled into cones of height $12 \, cm$ and diameter $6 \, cm$,having a hemispherical shape on the top. Find the number of such cones which can be filled with ice cream. [Take $\pi = \frac{22}{7}$]

$A$ cylindrical bucket,$32 \, cm$ high and with a base radius of $18 \, cm$,is filled with sand. This bucket is emptied on the ground and a conical heap of sand is formed. If the height of the conical heap is $24 \, cm$,find the radius and slant height of the heap. [Take $\pi = \frac{22}{7}$]

Selvi's house has an overhead tank in the shape of a cylinder. This is filled by pumping water from a sump (an underground tank) which is in the shape of a cuboid. The sump has dimensions $1.57 \, m \times 1.44 \, m \times 95 \, cm$. The overhead tank has a radius of $60 \, cm$ and a height of $95 \, cm$. Find the height of the water left in the sump after the overhead tank has been completely filled with water from the sump which had been full. Compare the capacity of the tank with that of the sump. (Use $\pi = 3.14$)