Two balls of the same mass, one of iron and the other of copper, are dropped from the same height. Which one would become hotter?

Explanation

As the mass and the height of both balls are the same, the initial potential energy (= mgh) is the same for both the balls. So the kinetic energy on impact with the ground will also be the same. Then, the same amount of heat will produced . We know that,
increase in temperature = `("heat produced")/("mass" xx "specific heat")`
But the specific heat of copper is lower than that of iron. So the copper ball will be hotter due to its higher rise in temperature.