Question

Please help me with my physics hw, thanks :) :D

Answer 1

Given:

The rate of decay,

`(dM)/(dt)=-kM`

The initial mass, M=150 g

To find:

The expression for the mass at any time t.

Step-by-step explanation:

On rearranging the given equation,

`(dM)/(M)=-\text{kdt}`

On integrating the above equation,

`\begin{gathered} \text{lnM=-kt} \\ \Rightarrow M=e^(-kt) \end{gathered}`

Final answer:

Thus the expression for the mass at any time t is

`M=e^(-kt)`

Therefore the correct answer is option A.