Answer:
[tex]-0.0067\ \text{cal/g/hr}[/tex]
Step-by-step explanation:
Energy of bird flight is given by
[tex]E=429w^{-0.35}[/tex]
Differentiating with respect to time we get
[tex]\dfrac{dE}{dt}=429\times -0.35w^{-0.35-1}\dfrac{dw}{dt}\\\Rightarrow \dfrac{dE}{dt}=-150.15w^{-1.35}\dfrac{dw}{dt}[/tex]
Now when
[tex]w=\text{Weight of bird}=10\ \text{g}[/tex]
[tex]\dfrac{dw}{dt}=\text{Rate of change of weight of bird}=0.001\ \text{g/hr}[/tex]
[tex]\dfrac{dE}{dt}=-150.15\times 10^{-1.35}\times 0.001\\\Rightarrow \dfrac{dE}{dt}=-0.0067\ \text{cal/g/hr}[/tex]
The rate at which the energy expenditure is changing with respect to time is [tex]-0.0067\ \text{cal/g/hr}[/tex]