if a boy sits on a slide and then slides down at a constant

if a boy sits on a slide and then slides down at a constant speed. Wouldn\'t the energy transfer be from potential to kinetic?? The answer states that it is potential to thermal energy which doesn\'t make sense to me

Solution

It is given that the boy slides down with constant speed. It means that component of its weight is balanced by the friction.

So, potential energy will be converted to thermal energy due to friction. Kinetic energy will remain constant.(given that the boy slides down at a constant speed)