- #1
Sandro Romualdez
Homework Statement
Three freight cars of equal mass are coupled together. The freight cars are traveling at 6.7m/s down a straight track when they collide with two more stationary identical cars. If all five cars are coupled together after the collision, then what is their speed if they are on frictionless tracks?
Homework Equations
Law of conservation of momentum: p=p' or m1v1+m2v2=m1v1'+m2v2'
The Attempt at a Solution
From the question I can figure out that
m1 = 3x
m2 = 2x
v1 = 6.7m/s [Down]
v2 = 0m/s
and I need to find vsys'
the msys after the collision will equal 5x
am I right if I use:
m1v1+m2v2=msysvsys'
→ (3x)(6.7m/s [D])+(2x)(0m/s) = 5x(vsys')
→ 20.1x kg·m/s = 5x(vsys')
→ vsys' = 4.02 m/s [D]
and the speed after the collision will be 4.02m/s [Down]?
Last edited by a moderator: