If the volume of a spherical ball is increasing at the rate of 4π cc/sec, then the rate of increase of its radius (in cm/sec), when the volume is 288π cc, is
Solution:
Given, volume of a spherical ball is increasing at the rate of 4π cc/sec
Volume of the spherical ball = 288π cc
We have to find the rate of increase of radius.
Volume of sphere = (4/3)πr3
288π = (4/3)πr3
72(3) = r3
r3 = 216
Taking cube root,
r = 6cm
On differentiating,
dV/dt = d[(4/3)πr3]/dt
dV/dt = (4/3)π(3r2)dr/dt
4π = 4πr2(dr/dt)
dr/dt = 1/r2
dr/dt = 1/(6)2
dr/dt = 1/36 cm/sec
Therefore, the rate of increase of radius is 1/36 cm/sec
If the volume of a spherical ball is increasing at the rate of 4π cc/sec, then the rate of increase of its radius (in cm/sec), when the volume is 288π cc, is
Summary:
If the volume of a spherical ball is increasing at the rate of 4π cc/sec, then the rate of increase of its radius (in cm/sec), when the volume is 288π cc, is 1/36 cm/sec.
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