Answer:
Explanation:
The mass of the train can be found by using the formula
[tex]m = \frac{2k}{ {v}^{2} } \\ [/tex]
k is the kinetic energy
v is the velocity
From the question we have
[tex]m \frac{2(2000000)}{ {20}^{2} } = \frac{4000000}{400} = \frac{40000}{4} \\ [/tex]
We have the final answer as
Hope this helps you