Ok? is this a question or what?
Answer:

Explanation:
g = Acceleration due to gravity at sea level = 
R = Radius of Earth = 6371000 m
h = Altitude of observatory = 4205 m
Change in acceleration due to gravity due to change in altitude is given by

Weight at sea level

Weight at the given height

Change in weight 
Her weight reduces by
.
Answer:
Q = 62 ( since we are instructed not to include the units in the answer)
Explanation:
Given that:



Q = ???
Now the gas expands at constant pressure until its volume doubles
i.e if 
Using Charles Law; since pressure is constant




mass of He =number of moles of He × molecular weight of He
mass of He = 3 kg × 4
mass of He = 12 kg
mass of Ar =number of moles of Ar × molecular weight of Ar
mass of He = 7 kg × 40
mass of He = 280 kg
Now; the amount of Heat Q transferred = 
From gas table

∴ Q = 
Q = 
Q = 62 MJ
Q = 62 ( since we are instructed not to include the units in the answer)