Answer:
22826.09 m/s
Explanation:
From the law of conservation of momentum,
Sum of momentum before collision = sum of momentum after collision.
For an inelastic collision, the train and the superman have a common velocity
Note: For the superman to stop the train in an opposite direction, the common velocity after collision is zero, and such the total momentum after collision is zero
Therefore,
MU + mv = 0
MU = - mu............................................ Equation 1
Making u the subject of the equation
u = -MU/m......................................... Equation 2
Where M = mass of the train, U = initial velocity of the train, m = mass of the super man, u = initial velocity of the superman.
Given: M = 75000 kg, U = 35 m/s, m = 115 kg.
u = -(75000×35/115)
u = -22826.09 m/s
Note: The velocity is negative because the direction of the superman is opposite the direction of the train.
Hence the superman have to fly 22826.09 m/s in the opposite direction
