Although if the second statement is saying that stars use gravitational force to support nuclear fusion which in turn produces energy then that would be correct, but I don’t think so :)
Stars are composed primarily of hydrogen and helium.
Explanation:
Stars are massive objects that have a large gravitational field, which drives the star to contract on itself, which is why fusion occurs: in the center of the star the nuclei of atoms are already so close due to gravity and high temperatures that bind. This is what is called nuclear fusion and is the energy source of a star.
On the other hand yes, the main elements of a star are hydrogen and helium (two hydrogen nuclei fuse to make helium), this makes the star mainly a huge ball of gas so there is no solid surface where you can stand on.
And about water on a star, that is not possible. Temperatures on stars are very vey high that watter could not exist in a liquid form on them.
The answer is 2.49 x 10^5 KJ. This was obtained (1) use the formula for specific heat to achieve Q or heat then (2) get the energy to melt the copper lastly (3) Subtract both work and the total energy required to completely melt the copper bar is achieved.
