How Long Does It Take for a Locomotive to Reach 32 m/s After Crossing?

[ferishta]

1. A locomotive is accelerating at 1.6 m/sec2. It passes through a 20.0-m-wide crossing in a time of 2.4 s. after the locomotive leaves the corssing, how much time is required until its speed reaches 32 m/s?

 

[hage567]

Hi ferishta,

You need to show some work in order to get help. What have you tried so far? What equations do you know that might be useful? No one is going to do your homework for you.

 

[Quang]

the initial velocity of the locomotive:
Vot + 1/2at^2 = s
=> Vo=6.41
the velocity of the locomotive when it just leaves the crossing:
V^2 - Vo^2 = 2as
=> V=10.25

32 - 10.25 = 1.6 x t
=> t = 13.6s

 

[ferishta]

Hey Quang,
Thanks for the help...I was really having a tough time becuase... I was not able to find the proper formulas to find, my physics professor expects us to know everything when it is an introductory course.
Thanks again,
Ferishta

 

[hage567]

Quang,

Please note that providing solutions to homework problems is against forum rules (the ones you agreed to when you registered here, by the way).

 

[ZapperZ]

As hage567 has mentioned, please review the PF Guidelines that you have agreed to. Pay attention to this section:

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[Quang]

i'm sorry... i didnt pay attention