A ball of mass 0.616 kg moving east (+x direction) with a speed of 3.90 m/s collides head-on with a 0.308 kg ball at rest. Assume that the collision is perfectly elastic. What is the speed of the .616kg ball after the collision? What is the .308kg ball after the collision?

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.

490 n

f=125n a=2.5m/s2

b. false

explanation:

suppose a rock in free fall is dropped off a cliff. after falling for 5 seconds, its speed would not be 100 m/s.

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.