Achild and sled with a combined mass of 50.0 kg slide down a frictionless hill. if the sled starts from rest and has a speed of 12.0 m/s at the bottom, what is the height of the hill?

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.

the answer is b, have negligible mass