A train has a mass of 1.5X10^7 kg. If the locomotive can exert a constant pull of 7.5X10^5 Newton, how long would it take to increase the speed of the train from rest to 85 km/h? (Disregard friction)
So far I have made a list:
mass(m)=1.5X10^7
Force(F)=7.5X10^5
Initial Velocity (Vi)=0 km/h
final velocity (Vf)=85 km/h
t=?
I'm not sure what to do now. I'm hoping that someone could EXPLAIN the process of how to figure out time. (PS. the answer in the book say it's 4.7X10^2 seconds)
2007-11-01 11:14:30 · 1 answers · asked by Qu'est ce que tu penses? 6 in Education & Reference ➔ Homework Help
You need two equations - one for force and one that takes in to account the velocities:
F = ma
vf = vi + at
You can use the force equation to find the acceleration that the force would impart on the mass. Then, using that, you can use the second equation since you know the velocities - just plug in and solve for the time t and you're set. Be sure to convert your velocities - the acceleration is in m/s^2, and your velocities are in km/h!
2007-11-02 07:02:36 · answer #1 · answered by igorotboy 7 · 1⤊ 0⤋