Answer:
The height of the right circular cylinder is 14/√3 and its radius is 7√6/3.
Explanation:
Check the attachment for the diagram.
The volume of a right circular cylinder = πr²h
r is the radius of the cylinder
h is the height of the cylinder
V = πr²h... 1
From the diagram, we can use Pythagoras theorem on the right angled triangle to get r². From the triangle P² = r²+(h/2)²
P is the radius of the sphere.
P = 7
7² = r²+(h/2)²
r² = 49-(h/2)²... 2
Substituting equation 2 into 1:
V = π(49-(h/2)²)h
V = π(49h-h³/4)...3
To get the height h of the cylinder, we need to differentiate the volume of the cylinder with respect to h and equate to zero. i.e dV/dh = 0 since it's the maximum volume.
dV/dh = π(49-3h²/4)
0 = π(49-3h²/4)
Dividing both sides by π
0/π = π(49-3h²/4)/π
49-3h²/4 = 0
49 = 3h²/4
3h² = 49×4
3h² = 196
h² = 196/3
h = √196/√3
h = 14/√3
To get the radius of the cylinder, we will substitute h = 14/√3 into equation 2
r² = 49-(h/2)²
r² = 49-{(14/√3)/2}²
r² = 49-{14/2√3}²
r² = 49-(7/√3)²
r² = 49 - 49/3
r² = (147-49)/3
r² = 98/3
r = √98/√3
r = √49× √2/√3
r = 7√2/√3
r = 7√2/√3 × √3/√3
r = 7√6/3
The height of the right circular cylinders is 14/√3 and its radius is 7√6/3.