MHT CET20249 May 2024Evening ShiftMathematicsApplication of DerivativesActual
A square plate is contracting at the uniform rate 3 ~cm ^2 / sec , then the rate at which the perimeter is decreasing, when the side of the square is 15 cm , is
Options
- A1 5 ~cm / sec
- B2 5 ~cm / sec
- C1 10 ~cm / sec
- D3 10 ~cm / sec
Correct answer
B. 2 5 ~cm / sec
Step-by-step solution
Let A , P and X be the area, perimeter and length of side of square respectively at time ' t ' seconds. Then, aligned & A=X^2, P=4 X & P=4 A aligned Differentiating w.r.t. t, we get aligned dP dt & =4 1 2 ~A dA dt & = 2 X dA dt & = 2 15 3 & = 2 5 ~cm / sec aligned array l side =15 ~cm dA dt =3 ~cm ^2 / sec array