Two balls, a and b, collide and stick together. ball a has a mass ma and ball b has a mass mb. before the collision ball a is moving in the +x direction with speed va and ball b is moving in the -y direction with speed vb . for what conditions are the two balls motionless after the collision? a. ma = mb
b. va = vb
c. mava = mbvb
d. mava = -mbvb
e. there is no such condition

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.