Let$$s consider another balloon, this time a

weather balloon. It$$s also made out of a thin,

easy$-$to$-$stretch rubber envelope, so the

pressure inside is approximately equal to the

atmospheric pressure outside. Suppose it$$s

filled with $800$ g of helium early in the cold

morning, when the temperature is $0$C$.$

As it waits for launch, the sun comes out and

warms the gas inside the balloon to $30$C$.$

This makes the balloon expand.

$($a$)$ What is the change in the balloon

volume?

$($b$)$ How much work is done by the

expanding gas?

$($c$)$ What is the change in the internal energy

of the helium gas?

$($d$)$ How much heat does it absorb from the

outside?