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Let I be the purchase value of an equipment and V(t) be the value after it has been used for t years. The value V(t) depreciates at a rate given by differential equation \frac{dV(t)}{dt}=-k(T-t);  where k> 0 is a constant and T is the total life in years of the equipment. Then the scrap value V(T) of the equipment is

  • Option 1)

    I-\frac{k(T-t)^{2}}{2}\;

  • Option 2)

    \; \; e^{-kT}\;

  • Option 3)

    \; T^{2}-\frac{I}{k}\;

  • Option 4)

    \; I-\frac{kT^{2}}{2}

 

Answers (1)

best_answer

As we learnt in 

Temperature Problems -

\frac{dT}{dt}= -k\left ( T-T_{m} \right )

- wherein

K is Proportionality constant

T = Temperature of body

T_{m}=  Temperature of Surrounding

 

 \int_{0}^{T}V(t)=\int_{0}^{T} -K(T-t)dt

V(t) -V(0)= -K(Tt-\frac{t^2}{2})|^T_0

V(t) -V(0)= -K(T^2-\frac{T^2}{2})

= \frac{-K.T^2}{2}

V(T )= V_0 -\frac{-K.T^2}{2}

V(T)= I-\frac{KT^2}{2}


Option 1)

I-\frac{k(T-t)^{2}}{2}\;

Incorrect

Option 2)

\; \; e^{-kT}\;

Incorrect

Option 3)

\; T^{2}-\frac{I}{k}\;

Incorrect

Option 4)

\; I-\frac{kT^{2}}{2}

Correct

Posted by

Plabita

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