Answer:
Collision will occur.
Speed of red train when they collide = 0 m/s.
Speed of green train when they collide = 10 m/s.
Explanation:
Speed of red train = 72 km/h = 20 m/s
Speed of green train = 144 km/h = 40 m/s.
Deceleration of trains = 1 m/s²
For red train:-
Equation of motion v = u + at
u = 20 m/s
v = 0 m/s
a = -1 m/s²
Substituting
0 = 20 - 1 x t
t = 20 s.
Equation of motion s = ut + 0.5at²
u = 20 m/s
t = 20 s
a = -1 m/s²
Substituting
s = 20 x 20 - 0.5 x 1 x 20² = 200 m
So red train travel 200 m before coming to stop.
For green train:-
Equation of motion v = u + at
u = 40 m/s
v = 0 m/s
a = -1 m/s²
Substituting
0 = 40 - 1 x t
t = 40 s.
Equation of motion s = ut + 0.5at²
u = 40 m/s
t = 40 s
a = -1 m/s²
Substituting
s = 40 x 40 - 0.5 x 1 x 40² = 800 m
So green train travel 800 m before coming to stop.
Total distance traveled = 800 + 200 = 1000 m>950 m.
So both trains collide.
Distance traveled by green train when red train stops(t=20s)
Equation of motion s = ut + 0.5at²
u = 40 m/s
t = 20 s
a = -1 m/s²
Substituting
s = 40 x 20 - 0.5 x 1 x 20² = 600 m
Total distance after 20 s = 600 + 200 = 800 m< 950m . So they collide after red train stops.
Speed of red train when they collide = 0 m/s.
Distance traveled by green train when they collide = 950 - 200 = 750 m
Equation of motion v² = u² + 2as
u = 40 m/s
s= 750 m
a = -1 m/s²
Substituting
v² = 40² - 2 x 1 x 750 = 100
v = 10 m/s
Speed of green train when they collide = 10 m/s.
