Amoving freight car runs into an identical car at rest on the track. the cars couple together. compared to the velocity of the first car before the collision, the velocity of the combined cars after the collision is group of answer choices

one half as large , initial velocity is two times larger

Explanation:

Momentum is conserved.

p₁ + p₂ = p₁' + p₂'

m₁v₁ + m₂v₂ = m₁v₁' + m₂v₂'

m₁ = m₂ =m , v₂= 0

v₁' =v₂'

mv₁ = 2mv₁'

v₁ = 2v₁'

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.