Answer:
3.) 463 J/g
Explanation:
Heat given by the fuel is used to increase the temperature of the water
so it is given as

here we will have
m = 250 g

now we also know that

so we have


so 3.5 g fuel gives above energy
so per gram of fuel will have total energy given as


Answer:
The mass of the cargo is 
Explanation:
From the question we are told that
The radius of the spherical balloon is 
The mass of the balloon is
The volume of the spherical balloon is mathematically represented as

substituting values


The total mass the balloon can lift is mathematically represented as

where
is the density of helium with a value of

and
is the density of air with a value of

substituting values


Now the mass of the cargo is mathematically evaluated as


A haha snake e enajene. skskskksksks and
Answer:
the first one is Primary
the second one I think it's Mature but I don't know