Simple Acceleration and Velocity Problem

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Homework Help Overview

The problem involves a train's motion along a straight track, with its position described by a cubic function of time. Participants are tasked with finding expressions for velocity and acceleration, as well as determining constants based on given conditions.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to derive expressions for velocity and acceleration from the position function. Some participants confirm the correctness of the original poster's calculations, while others express confusion about the discussion.

Discussion Status

The discussion includes confirmations of the original poster's findings, with some participants acknowledging potential mistakes in their own understanding. There appears to be a mix of validation and uncertainty regarding the calculations presented.

Contextual Notes

Participants note the original poster's lack of access to a textbook, which may influence their confidence in the solutions provided.

veronicak5678
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Homework Statement


A train travels along a straight track. Its position is given by x(t) = At^3 + Bt from t = 0 to t=5.0 s.
a- find an expression for the velocity.
b- find an expression for the acceleration.
c- if the train has an acceleration of 2.00 m/s^2 and a velocity of 10.0 m/s at t=5, find 'A' and 'B'.


Homework Equations



v= dx/dt

a = dv/dt

The Attempt at a Solution



I got 3At^2 + B for velocity and 6At for acceleration. I got (1/15) for 'A' and 5 for 'B'. I don't have a book yet and just wanted to make sure i understand what I'm doing. Any help would be appreciated!
 
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Looks good to me.
 
Sorry, I don't know what you mean...
 
veronicak5678 said:
Sorry, I don't know what you mean...

No you did it right. I made a hasty math mistake.
 
Great. Thanks for your help!
 
I'm saying your answers are correct. :smile:

EDIT: methinks I missed something here :rolleyes:
 

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