A train have a Mass ofM.It pulls in a horizontal plane against the resistance forceR.The Engine works at the same rate ofH,(U<$\displaystyle \frac{H}{R}$)

1.WhenRis constant,Show the time take by the train to assumeUfrom rest is$\displaystyle \frac{MH}{R^2}ln\frac{H}{H-RU}-\frac{MH}{R}$

In this problem, LetPbe the pull of Engine Then ,(P)(U)=HIs It Correct Or Not???????