MHT CET202120 Sep 2021Evening ShiftMathematicsApplication of DerivativesActual
The surface area of a spherical balloon is increasing at the rate 2 ~cm ^2 / sec . Then rate of increase in the volume of the balloon is , when the radius of the balloon is 6 ~cm .
Options
- A4 ~cm ^3 / sec
- B16 ~cm ^3 / sec
- C36 ~cm ^3 / sec
- D6 ~cm ^3 / sec
Correct answer
D. 6 ~cm ^3 / sec
Step-by-step solution
We have dA dt =2 and A =4 r ^2 aligned & dA dt =8 r dt dt 2=8 (6) dr dt & dr dt = 1 24 aligned Here V = 4 3 r ^3 aligned & dV dt =4 r ^2 dr dt & =4 (6)^2 ( 1 24 )=6 ~cm ^3 / sec aligned