Amountain-climber friend with a mass of 74 kg ponders the idea of attaching a helium-filled balloon to himself to effectively reduce his weight by 25% when he climbs. he wonders what the approximate size of such a balloon would be. hearing of your physics skills, he asks you. share with him your calculations that find the volume of the balloon.

Explanation:

The volume of the balloon can be find compared the force in each cases so:

reduce 25% from 74kg

So the net force uproad on the balloon is

Now the density of the both gases air and helium are different however the volume is the same change offcorss the mass so:

d. air pressure decreases as altitude increases.

i think its c if i'm wrong