Explanation:
Distance = Total path length = 35m + 35m = 70m
Displacement = Final - Initial position = 0m
The first one is C. Hope this helps!! If you need anymore help just message me and I will try to get back to you quickly and help in any way i can!
a) Density at 100 degrees: 
Explanation:
The density of mercury at 0 degrees is 
Let's take 1 kg of mercury. Its volume at 0 degrees is

The formula to calculate the volumetric expansion of the mercury is:

where
is the cubic expansivity of mercury
V is the initial volume
is the increase in temperature
In this part of the problem, 
So, the expansion is

So, the new density is

b) Density at 22 degrees: 
We can apply the same formula we used before, the only difference here is that the increase in temperature is

And the volumetric expansion is

So, the new density is

An VIRTUAL image cannot be projected, and
forms where light rays appear to originate.
-It takes air from it's surroundings.
-Compresses the air
-Removes Nitrogen
-Delivers an electric Interface
-Then it delivers the purified oxygen