Answer
(a) increase
(b) $8.2W$
(c) $12W$
Work Step by Step
(a) We know that $P=Fv$. This equation shows that power is directly proportional to the velocity when force is constant. In the given scenario when an apple falls, the force of gravity is constant but the velocity increases. Hence, the power delivered to the apple by gravity will also increase.
(b) We know that
$v^2-v_{\circ}^2=2g\Delta y$
$v_{\circ}=0$
$\implies v^2=2g\Delta y$
$\implies v=\sqrt{2g\Delta y}$
We plug in the known values to obtain:
$v=\sqrt{2(9.81)(3.5-2.5)}=4.4\frac{m}{s}$
Now we can find the required power
$P=Fv$
$\implies P=mgv$
We plug in the known values to obtain:
$P=(0.19)(9.81)(4.4)$
$P=8.2W$
(c) As $\implies v=\sqrt{2g\Delta y}$
We plug in the known values to obtain:
$v=\sqrt{2(9.81)(3.5-1.5)}=6.3\frac{m}{s}$
Now we can find the required power
$P=Fv$
$\implies P=mgv$
We plug in the known values to obtain:
$P=(0.19)(9.81)(6.3)$
$P=12W$
