Answer:
The trains stop 69 meters apart.
Explanation:
For each train, we're given the initial velocity, final velocity, and acceleration. We want to find the displacement. So we need to use an equation that's independent of time:
v² = v₀² + 2aΔx
First, convert km/h to m/s:
100 km/h = 27.8 m/s
128 km/h = 35.6 m/s
For the first train:
(0 m/s) = (27.8 m/s) + 2 (-0.9 m/s²) Δx
Δx = 429 m
For the second train:
(0 m/s) = (35.6 m/s) + 2 (-0.9 m/s²) Δx
Δx = 702 m
The first train moves 429 m before stopping, and the second train moves 702 m before stopping. They move a total distance of 1131 m. They were initially 1200 m apart, so they stop with 69 m to spare.
