Answer:
0.1667 m/s
Explanation:
m1V1 + m2V2 = m1V3 + m2V4
0.01 = ( 0.0075) + (0.015 * V4)
V4 = (0.01 - 0.0075) / (0.015)
V4= 0.1667
It is typically 30 km to 50 km thick.
Answer:

Explanation:
consider the mass of each train car be m
m₁ = m₂ = m₃ = m
speed of the three identical train
u₁ = u₂ = u₃ = 1.8 m/s
m₄ = m u₄ = 4.5 m/s
m₅ = m u₅ = 0 (initial velocity )
final velocity
v₁ = v₂ = v₃ = v₄ = v₅ = v
using conservation of momentum
m₁u₁ + m₂u₂ + m₃u₃ + m₄u₄ + m₅u₅ = m₁v₁ + m₂v₂ + m₃v₃ + m₄v₄ + m₅v₅
m (1.8 + 1.8 + 1.8 +4.5) = 5 m v

