A freight train has a mass of 4.5*10^7 kg

[Fanjoni]

A freight train has a mass of 4.5*10^7 kg. If the locomotive can exert a constant pull of 15*10^5 N, how long would it take to increase the speed of the train from rest to 85 km/h?

I know u need to use F=ma but how do i find time

 

[gunblaze]

Think! What are you trying to find by using F=ma? Clue: You do need to use a little kinematics in this qn. If u have acceleration, final velocity and initial velocity, how are you goin to find time?

 

[civil_dude]

Also remember to use the correct units, i.e. don't use km/hr.