Answer: The original temperature was

Explanation:
Let's put the information in mathematical form:





If we consider the helium as an ideal gas, we can use the Ideal Gas Law:

were <em>R</em> is the gas constant. And <em>n</em> is the number of moles (which we don't know yet)
From this, taking
, we have:
⇒
Now:
⇒
I’m pretty sure it just wants you to list the property’s meaning the material and density
Answer:
Speed at which it will reach the ground is given as

Total time for which it will remain in air is given as
t = 6.3 s
Explanation:
As we know that the object is projected upwards with speed


now when it will reach the ground then we have

so we have


so we have

Now speed of the object when it reaches the ground is given as


