Answer:
a. 
b. 
Explanation:
Using the triangle theorem both triangle the woman makes between the light so the rate of change of length can use geometry first

Solve to find the rate relation


Now the rate of the change rate


Finally the rate of her shadow moving


You can calculate potential energy by:
U = m.g.h
Where, U = potential energy
m = mass
g = acceleration due to gravity
h = height
Hope this helps!
D, 0.140 liters! Hang on a sec and I'll show you a trick I use.
Answer
A thin atmosphere does not supply much oxygen, and the heat from the sun would evaporate it, because mercury is close to the sun.
The acceleration is the correct answer