Physics Question on Motion: Object Acceleration and Distance in Uniform Motion

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Homework Help Overview

The problem involves an object accelerating uniformly, specifically focusing on its distance traveled during specific time intervals. The original poster seeks to determine the object's acceleration and total distance traveled over a set duration, with particular emphasis on the distance covered in the eighth second of motion.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the equations of motion and their applicability, questioning the initial conditions and the interpretation of the problem statement. There is uncertainty regarding the initial velocity and how to derive acceleration from the given information.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some suggest that the object starts from rest, while others question this assumption. There are attempts to derive equations for distance traveled over time, but no consensus has been reached on the correct approach or values to use.

Contextual Notes

Participants note that the problem does not explicitly state the initial conditions, leading to varying interpretations of the object's motion at the start. The focus is on the distance traveled during specific seconds, particularly the eighth second, which adds complexity to the analysis.

einstein101
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Homework Statement


An object that is acclerating uniformly travels 22.5 m in the eighth second of its motion.
a) what is the acceleration of the object?

b) how far does the object travel in 6 seconds?


Homework Equations


I'm not exactly sure what equation would be necessary-
perhaps -- a=v-u/t
v=u+at
x=ut+1/2at^2


The Attempt at a Solution



i attempted to use the a=v-u/t equation, however, it wasn't successful. I don't even think you can use that equation since we don't have the values for velocity;initial nor final.
 
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The object has no motion at t = 0. How far does it travel in 8 seconds? How far does it travel in 7 seconds? Its displacement between the. 7th and 8th seconds is given as 22.5 m. Use your last equation.
 
Hi einstein101. The eighth second is that time difference between seven seconds and eight seconds.

travel during first 7 seconds= u.7 + (1/2)a.72

travel during first 8 seconds= ?
 
But how do I find the initial velocity for the equation?
And how would I exactly go about finding the acceleration?
 
PhanthomJay said:
The object has no motion at t = 0. How far does it travel in 8 seconds? How far does it travel in 7 seconds? Its displacement between the. 7th and 8th seconds is given as 22.5 m. Use your last equation.

It says nowhere that the object started from rest.
 
e^(i Pi)+1=0 said:
It says nowhere that the object started from rest.
It says "in the eighth second of its motion". I would interpret that to mean that it started from rest.
 
einstein101 said:
But how do I find the initial velocity for the equation?
And how would I exactly go about finding the acceleration?
Can you finish the equation I left uncompleted?
 
Doc Al said:
It says "in the eighth second of its motion". I would interpret that to mean that it started from rest.

Hmm, I suppose you're right.
 
so travel during first 8 seconds=u x 8 +1/2(a)(8)^2

then what do i do?
 
  • #10
einstein101 said:
so travel during first 8 seconds=u x 8 +1/2(a)(8)^2

then what do i do?
Good. Now subtract that from the companion equation I gave you, viz., of distance traveled during first 7 seconds.
 
  • #11
einstein101 said:
so travel during first 8 seconds=u x 8 +1/2(a)(8)^2

then what do i do?
It has been established that the object starts from rest and thus u = 0 and the distance traveled in 8 seconds is 32(a). In a similar manner, find the distance traveled in 7 seconds. Subtract this 2nd equation from the first equation and set the result equal to 22.5 to solve for a.
 

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