First, convert all the km/hr into m/s
You will get that
initial speed = 20 m/s
Initial speed of Green train = 40 m/s
Initial separation = 950 m
Velocity of approach = 20 - -40 = 60 m/s
relative acceleration = -4 m/s^2
v = u + at
0 = 60 - 4t
t = 15s
s = ut + 1/2 *at * t
s = 60 * 15 - 1/2 *4 * 225
s = 900 - 450
Separation when they stop = 450 m
hope this helps
The force ffrom the ground that holds the rock up and prevents her from falling through the gound, unless the ground breaks.
-- The mass of the sun never increases.
-- It does decrease, but not nearly enough to have any noticeable
effect on the orbital motion of the Earth, or any other planet.
-- When Earth is closer to the sun, it moves faster in its orbit.
-- When Earth is farther from the sun, it moves slower in its orbit.
-- The result is that the line from the sun to the Earth always covers
the same amount of area in the same length of time.
-- Johannes Kepler noticed this, and it's his Second Law of planetary motion.
-- Newton showed that if his equations for gravity and motion are correct,
then planets MUST behave this way.
It is the first on differences in water temperature.
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